This is one of these “whatever you think” questions. If you survey a bunch of moms, you will find that each one has pros and cons to the spacing that they chose. So maybe the answer lies in which set of pros/cons most appeals to you.
One or Two years Apart
All my children are less than eighteen months apart, and this has some distinct advantages. Firstly, they are all best friends. They go through the same stages, pretty much right after the others, and sometimes overlapping. The rules are the same for everyone, they play with the same toys (mostly), and they learn from one another–both academics and morally. I pretty much have just one code in the house at all times and this works well for everybody. The first was a late bloomer, the next child was average, and the younger two are precocious (from learning from their older siblings). All the siblings needed to learn how to share and not steal as babies, so they work well together with just occasional squabbles over stuff. And they can share a room, watch the same videos, and keep each other happy in the car or anywhere else. It is not a utopia or anything, but having your children close together is a very special thing for them. When they come close together, there is less chance of resentment… our children were only toddlers when the next new person came along, so they accepted each new person happily as if they were always there. They are also very cute on the parental end. Babies closer to a year apart feel like twins =) You can really get into the swing of things and just laugh or admire them all day. You have a sense of preciousness about your home. Plus, with your children spaced close together, you can have more children easily if you are interested as well as get over certain stages (i.e. like diapers and carseats) sooner.
On the disadvantages, there is much more work involved. Safety and decorum-wise, you have your work cut out for you. It is much harder to keep cool, not stress over development, and find peace. You are usually battling these things from a day-to-day standpoint. You always encounter the same problems, in one child after the other, and you can say the same thing all day long to everybody… things like “share with your brother” or “don’t put that in your mouth,” or “let’s use the toilet now” can go on for four or five years straight. So you have to be ok with a large amount of monotony, or innocent to it. Also the intensity involved in making sure everyone has the attention, love, health, discipline, and opportunities they need goes way up… one toddler finger-painting is enough for most people, but would you like to have two or three? You’re more likely to put a lock on the art cabinet and say No Way. The same for going to the grocery store. With just one two-year old, you brave it with some problems. With a four year old and a baby as well, you’re likely to hire a babysitter and go out to the store for your own “date night.” And there is definitely more competition potential, or more of a comparison mentality, when the children are in the same peer-age group.
Just a quick note: my babies who were spaced closer to a year apart seemed to have less trouble adjusting than my friend’s babies who were spaced closer to two years apart. Two-year olds must have a notoriously difficult time when the baby sibling arrives, but my fifteen month olds barely noticed!
So having more children is more work up front, and more irritation, more vigilance, more stress. But in the long run, most parents of siblings that are close together say it was worth every sacrifice… I have heard this even from the siblings, on the grown-up end. If you want more than two children, it is definitely something to consider for their benefit.
Three or Four years Apart
From an educational or psychological perspective, having your children three to four years apart comes highly recommended. So if you are a development guru, this spacing is for you. The siblings are old enough to not regress much, and the older ends up teaching the younger a lot. Or entertaining them. A three-year old can “help” with the baby, and very soon learns to protect and cherish them. You can pay more individual attention to each child because the older is more independent, wanting more skilled play, and the baby has a different set of needs which ministers to the tender aspect of mommy’s heart. For you, this can be more fun. Activities are more diverse… while one is still in diapers, the other is just starting school. And most parents with children three or four years apart felt more ready by the time the second or subsequent child came along, both physically and emotionally. The baby stuff was brought out of storage with joy, and Dad could easily entertain the four-year old while Mommy was in the hospital with the newborn. The siblings do not compete as much, and the older-younger dynamic really takes hold, for the better.
On the other hand, there is definitely a chance for sibling rivalry when the next sibling comes along. The “baby” of the family will almost always be displaced, and it will be harder to emotionally reassure them than if they were younger. Also, the siblings do not share as many life events as they would if they were closer together. The older-younger dynamic is bonding, but maybe not as bonding as the peer dynamic you get when the children are spaced more closely. They will be apart cognitively, so rules will need to be different, expectations, responsibilities, and that sort of thing… probably the main trigger of resentment. And they will be separate in their educational experience: when one goes off to school, the other is left behind (both in the preschool and college years), and there is less overlap of when the children go to the same school (as in, one in middle, one in high school). This is important because school is so large a part of children’s live, and the kids will almost definitely have different friends, activities, worries, and issues. It is the sharing of these types of things, however, that creates the lasting (interdependent) bond in your adult child’s mind. When your children who are more spaced apart grow up, they will love one another deeply but in a more independent way. Distance between two siblings three or four years apart is manageable, but it may be hard for oldest and youngest to bond if a third is introduced, also that width apart.
Five or Six Years
Spacing your children five or six years apart is a little rarer than a spacing of three or four years, but it is more common now that mothers feel significantly more freedom concerning how to fit their work and childbearing years together; this generation has more options than ever before. I think this is a really good thing because what is right for one family may not be right for another, and having your children five or six years apart can be really fulfilling. Sometimes this happens when Mom is having trouble getting pregnant again. Other times it happens when there is a miscarriage. Other times it happens when Mom or Dad are not sure they want another child and need some time to figure it out. When your first child hits the ripe age of five or six year and they are over their “little child” stage, a sense of relief or accomplishment may trigger the “ok, maybe we can have another one after all” response.
Because your first child is in school by then and probably over the hump of needing ridiculous amounts of attention and worry, having another baby at this time can be really nice. You have another new one to love and lots of time (at least during school hours) to love them. You can breastfeed and wander around in your pajamas more, but the children are not so far apart that the older cannot appreciate the younger. You will definitely have an older-younger dynamic going on, but sometimes this is a real source of pride for the older child because they are old enough to understand what having a sibling really means, and can help more significantly than a three or four year old.
That said, your older child may feel they have a longer time to wait before they really get to relate to your younger. Five and six years is a small lifetime to children, and it may be hard for them to understand why their baby sibling is eating their legos, gnawing their school papers, and generally taking up all your time. I’m not sure they’ll be resentful as much as neglected. The tendency to feel like your five and six year old can handle themselves is more tempting than if they were in preschool, so you have to make extra special time to join them in their little worlds; they are still sensitive and just starting to enter the world of youths. On your part, you will feel like you are trying to meet the needs of two very distinct individuals, separate from one another, and this isn’t bad—just different.
Seven or more years apart
I put this category distinct from five and six years apart because once you get beyond about six years spacing, the older sibling becomes more like a parent to the younger. Granted, a seven year old is not very “old” when your baby arrives. But by the time your baby is two and three, you will have an almost baby-sitter on your hands as well. Siblings that are spaced this far apart rarely bond the same way that sibling spaced less apart do. And this can be very good or very bad; sometimes the sibling pair really hits it off and the older has a soft spot for their baby. But you have to help create this dynamic through modeling and opportunity. Otherwise, the temptation is to get two very independent people who just happen to live together, or an older sibling that resents having to take care of themself and the younger baby. So you have to watch out for this.
That said, I know two mothers who have had children almost a decade apart, and three of them—one in the twenties, one in the thirties, and one in the forties. These mothers may have had their first too early when they weren’t really ready and then went back to career. They enjoyed working and had the second when they were really ready, in the early thirties when other people were having their babies. Then when they were thirty-nine or forty they had an “accident” pregnancy or just decided they wanted to have another baby in life. And they really liked this. I think they liked it more than the siblings did. For whatever reason, it was really fulfilling for them to bring up children eight to ten years apart, and they felt like a completely different person each time they had a baby. I don’t know about how the siblings will feel about this when they’re older… I suspect they will find it harder to relate. But maybe not if they live close together and can start a good relationship when they’re older.
A lot of this information can be seen by observing not just families with a couple children spaced apart but families with multiple children where the older and younger are spaced farther apart with middle siblings in between: a lot of the dynamics concerning years apart still hold, even though there are mediate siblings. However, in the case of having many children, you often get a “pairing” phenomenon where certain sibling pairs really hit it off. A teenager may have a special affinity for their two or three year old sibling. Or two middle children who were born closest together may act like twins. Or any other kind of combination! This can be very cute, but you also need to work hard at preventing “cliques” which would overly exclude others; children can benefit from all kinds of sibling relationships, even those that are less natural, if you as the parent work at it a bit.