Don't call someone's bluff without a reason to think they are bluffing, such as them raising A LOT, or having previously seen someone else call them and discovered they are bluffing. Even then, it's best if you can wait until you have a feel for how good the person is and what types of spots they bluff.

In low-limit cash games, I agree that bluffing is very limited. People don't worry enough about what could beat them for it to be profitable. There are times that it will work, but you must have reads on other players and know that they will lay down hands. Usually, I'd restrict it to late position plays and/or semi-bluffs.