Age gaps between children - thoughts please!

[Mississippilessly]

We have a 7 month old son. He is a poor sleeper and a high needs baby. We always planned on 2 children and despite how hard DS is we really do want a 2nd.
I will go back to work when DS is a year, I've gone from full time middle management to 3 days non management. The drop in pay is considerable. I am a teacher so it is worthwhile trying to plan when I get pregnant (although obviously it doesnt always work like that!)

We would hope to have a 2nd when DS turns 2. Our logic is get the baby and toddler stages done all in one go.

What are the age gaps for your children and would you recommend it?

I have 3.5 yrs between eldest two and 4 years between the youngest two. It was great when they were little as they were at nursery or school when i had a new baby, so could give them their own time.
They're 8, 12 & 15 now and it works ok. The younger two used to play together a lot, but now he's becoming more teenagery , he isn't so interested anymore 😞