It really depends on your situation, what you want and if you had any issues TTC with #1. We wanted about 3 years between ours and given that we conceived DD first try we thought that we had better take that into conideration when TTC#2. This was a good idea as we concieved first try again and we will have almost exactly 3 years between them. However, if we didn't concieve immediately we would have been happy to keep trying.