In your opinion, how much time should p before having another child?

Our daughter is 3, and we are trying for baby #2 now. I will say that when she was little, I swore I wouldn't want another til our daughter was 5, but that has definitely changed! I second the waiting til the first one is potty trained. It seems like it would make things much easier. Although I had a friend who got pregnant with her second child when her first was only 12 mos and she said it wasn't much more difficult, she was already changing diapers, now it was just double the diapers. I kinda wish we had another one sooner though.