I have two boys aged 12 and 10 , 21 months apart , a girl aged 9, 13 months younger than the 10 year old, so all a few weeks over 3 years apart in total, then a baby boy aged 5 months, so 9 years younger than my daughter.
I found the 3 practically under 3 a struggle , not sure how I managed it, the boys used to get on alot when little and the younger one, skipped baby toys and baby tv and went straight to superheros, jumping of tthe couch, and the 2 year old toys along with his brother... Now they are older, they really do wind each other up and fight all the time, (but their sharing a room, so may not help!)
My daughter and the 13 month older boy, do get on just fine, only when the older boy is not around!! it's really nice to see, as they are so close in age even tho different genders. When the older boy is back, arguments break out within minutes, but then he is nearly a teanager..... it could get worse...
The gap between the 3 kids and my baby is fantastic, from someone who wanted all her kids close together , now is a convert to huge gaps in age! I have soo much more time available for my baby compared when my kids were all tiny, and feel he will end up getting a huge input , as all the others will be at school and then older off doing their own thing etc...
But my three grew up together. My little Devon may get lots of time, but may not have his siblings about much and will need a good base of little friends his own age.
There never is the perfect gap , there are pros and cons for both
Do you mind me asking , what age gap do you currenty fancy and why?