It really depends on the track. Actually it's a good idea to always do it, but how much?
Start out with minimum decay and a low mix. Then bring up the mix and decay until it sounds right. If you have each type of instrument (lead, chord, bass, drums, etc) on their own busses, before they go into the master, maybe bus all those into a final two: drums and instruments. Then put separate reverbs on each. A smaller one on drums, and a slightly louder and larger reverb on the instruments.