It depends of your stack and your position and the profile of other players. You must gather some evidence of what players might believe your bluff (usually tight players) and you'd have to be in position to make a good decision.
And it depends your own image of the table. If you play tight, the more other players might believe your bluff. The more you bluff, the less effective it becomes.
And of course, there's good RNGesus, there were times I bluffed, got called, had the worst hand, but won because RNGesus was at my side. Don't count on that.
Cheers.