As a general rule (and I know there are very few general rules in poker), do you bet top pair on a low board the same way you bet it on a high one? For instance, if you have AK, and the board comes up 2-9-K, a pot-sized bet is standard. Now, say you have 89, and the board comes up 2-5-9. Do you make the same standard bet, knowing that an overcard is likely on the turn or river?