Well only you can answer that really. 2.5 years is the minimum I would have between kids even though I always have intense baby lust after my babies are born.
I lose my milk with pregnancy, and I want my children to be old enough to not supplement. I want them to be potty trained or nearly potty trained. I want them to have a good amount of time being the baby. I get severe hg, and I couldn't handle it with a younger baby.