When Should I transplant

Thi is only my 2nd grow and the first one went threw alot it was throw out a window and half dead so i put it into a bigger pot it grew up healthy I used no Plant foods just water and I have to get ride of it cause it was male. But now I'm trying to find the best time it would be to transplant my plants into bigger pots.

Since your question is very vague and general, without any other useful information
as to size of the pots you have now, how old they are, and no pics included with your post...
... the answer will be vague and general.
Transplant them when they are too big for the container.