You must always try and add tricks and lets say dishonesty to your game in order to stand a better chance of not getting read by the other players. If you always check when your hand isnt great, but not as bad to fold, and if you always bet or raise when you have a very good hand that requires a risk then you are playing it honest all the way. And this can turn against you, because other more attentive players can figure out your game pattern and they might use their new knowledge to control your game.
When you are on the flop and you are the last or among the last players to take an action, then you can just raise the bet with a drawing hand here. It is very possible that our opponents check when the turn comes and you can also check in this case if you dont get the cards you need or expect. However if you get what you needed you can bet as well here. The whole situation you have created this way will end up saving you money when you check and your hand doesnt become better and it will make you win a lot of money when your hand gets better. If the situation occurs and you are re-raised by another player it will cost you more money than predicted but it would be worth it...