How long have they been in those pots? May be time to go up a size. If it seems like you need to overwater just to keep them from drooping the roots need more room.
The other thing it could be is bad drainage. If the water pools up and goes over the sides when you water instead of running right through you can add aeration in the form of perlite to improve drainage.
Drooping is almost always from either a lack of or too much moisture at the root zone. The roots either lack access to O2 or moisture; you just gotta figure out which.