Well, my opinion would be 2-3 years. We were going to have ours two years apart, but when our daughter was at the age where it was time to try again I realized I wasn't ready quite yet lol! So when she turned 2 we started trying again. She'll turn 3 a month before the new baby comes, and I feel really good about that age gap. She finally is potty trained, so I won't have TWO in diapers. Just my opinion though!