I think more info will be needed:

How long do they hold up and how long would you like the to hold up?
What are you running them in?
What battery are you running? (mostly the mah rating)
How much charge does it accept after a run?
Do you run accessories like fans / external BEC etc in there?

Things that can impact your charge are driving style for sure, if you are aggressive getting on the throttle and brakes you will run it down faster. Or sometimes some ESC settings can play a part like drag brake.