This is something I think about often. Does raising children get harder as they get older? I often think it does. But then sometimes I think it doesn't. Let me explain. Or at least try.
FYI, My kids are 6, almost 9, almost 11 and 12 1/2.
:::Disclaimer, in case anyone didn't know, I love my kids, I've loved them at every age and I will forever, complaining about things they do is a normal part of parenting. These are just observations from my experience, not fact.:::
Babies. When I hear about people struggling with a new baby, I think to myself, Please, that part is the easiest. All they do is sleep, eat, and poop. And cry. They do tend to cry. I guess looking back it's not as fresh in my memory so I'm probably forgetting a lot of crap. Like you loose sleep, it can be physically demanding, especially if you breastfeed. You have no time to yourself. Wow. I guess it's not so easy. The good part is they are so sweet and adorable when they're happy or asleep. The first smile? Euphoria.
The toddler age is worse. When they get to the toddler stage they just get into everything. They seem to constantly be making a mess or doing something they shouldn't be like sticking a hairpin into a socket, (Happened.) or dropping eggs on the floor for fun. (Also happened. Hey I never claimed to be mother of the year.) You have to clean up their solid food poo when they have accidents during potty training, which is not cute at all. Really, whenever I am around people who have kids at this age I'm so glad my kids are older. They tend to be snotty sometimes, and they start whining. On the other hand, toddlers can be hilarious when they start to talk and they are still really innocent.
I'm going to go out on a limb here and say that Kindergarten age is a great stage. The kid can wipe it's own butt , feed and dress itself, and they are still excited about school and are happy most of the time. It might help that they do go to school for several hours a day as well. Kids at 5 or 6 still listen to what you say most of the time. They aim to please. The only down side I can think of is the incessant talking. Don't shut up, that bunch.
Now kids that are from around 7-10 start to realize, Hey, I'm my own person! I have ideas and opinions! I shall assert them! This can be good and bad. They begin to challenge you just because they can. Test their limits on things like ignoring you or doing as their told, but they are still pretty sweet and try to make you happy by thinking of creative ways to show they care. Notes and helping out, it's the good side of being free thinkers. They start having their own sense of style as well and begin to care about their appearance more. Well girls do anyway.
For the tweens (10-13) They really start in with the attitude. Eye-rolling, sighs and complaints are aplenty. They start to smell in these years so hygiene must be stressed. The boy doesn't seem to be bothered about his looks yet but Girls this age really begin experimenting with their hair, clothes, products, skin care. It's all good with me as long as they shower and the good part is they can shower on their own, of course for a while now, so you just buy them deodorant and they're good to go. Good part, tweens are really almost young adults so you can have actual conversations about topics and enjoy some of the same movies sometimes. It's great in that respect.
After that, it's yet to be seen for me. I'm definitely worried about the teen years as most parents are. I'll let you know how it goes.