there are a few things that can be looked at.
1-check for a leak (underground?)
2-check pressure in the tank
3-check the adjustment on the pressure switch
4- do you have a filter that may need changed
5-do you have a water softner that you can put on bypass to see if that helps.
6-do you have a bad main shut off valve that is restricting the flo of water?
7-check the pressure guage and see what the pump kicks on at and kicks off at.
Hope this helps 30 on 50 off is good but 40 on 60 off is better make sure you have 2 lbs less air pressure in the Bladder tank than the cut in on the pressure switch.