im having trouble deciding to go 3 sets or 4 sets

for example on chest day

Flat - 3 or 4 sets each ?

incline - 3 or 4 sets

decline - 3 or 4 sets ?

flys - 3 or 4 sets? - what would u do

i've been doing 4 sets each and seen good results but i do abs and cardio every single workout also, and my wrkout is dragging to a huge 2.5 hours a day when i do more weight longer rest

i wanted to cut down on time a bit, but then i switch to 3 sets and feel like im not gettin the pump i want.. any opinions from personal experience on the matter?