I play a lot of 1/2 and 1/3 live games. I frequently get into a position that I am heads up to the flop make a continuation bet then check back the turn with less than top pair (pocket QQ or JJ on an A,10,4 board). A lot of the regulars I play frequently float the flop with the intention of taking down the turn or river. When I am out of position and check the turn they bet with a very large portion of their range (any pair or reasonable draw). So the question is there any rule of thumb to follow on the turn and river calls on my part?