Haven't read all the other comments so if i am redundant forgive me. I think with 3 or 4 opponnets betting into them with nothing does not have any bluff value. I have been called down with a pair of twos and broadway cards on the board to lose with my ACE high.
Most of the time I would be taking my free card on the flop. If I have only 2 opponnents I betting to the turn and checking behind on the river.
The question is do you bet the flop hoping for a free card if unimproved or check through for the free card now and reevaluate the turn.
If the field is really passive and I think the board looks uncoordinated enough that I won't get checkraised I might bet the flop with the hopes of getting a free card on the turn. If I have a serial checkraising LAG out there who is trying to thin the field and get heads up with me with his bottom pair with K or A kicker I would just check the flop and reevaluate the turn.