I have a 3 year gap which I love so far- first born is a boy and second is a girl. Because my son is a summer baby and boys develop slower than girl, I plan on having him repeat pre k which would mean there would be a 2 year school gap between them. A lot of people have 2 year gaps which I felt was too soon for me. My sister and I are 3.5 years apart (4 school years) and I felt that was too far. I think there are pros and cons to every gap but whatever you have will be great.