Welcome to TFP.
Pump run time is dependent on NEED.
You run you pump for a reason:
1) skim
2) add chemicals (dosing pumps, SWCG etc.)
3) Mix chemicals when you are adding to the pool
4) Vacuuming if you have a suction side vacuum or pressure side vacuum
5) Filtering
6) Heating (heater or solar or whatever), or chilling (chiller)
7) to run your spa, jets, waterfall or whatever other feature that is water driven...
Run your pump as long or short as you need to accomplish these tasks to your liking (i.e. skimming clean enough for you, filtering to get the water clarity you want, adding enough chemicals to maintain the pool, etc.)