I hate generalizing, but I'm going to do it right now. Lots of player slowplay way too often. Especially in lower buy-in tournaments, and micro cash games, where there's really no need.
At these smaller stakes, players are for the most part playing level 1 poker. If they have a hand they're coming along for the ride, if not then they're ditching. Checking to slowplay in a lot of these situations is not a good EV move since you could likely extract three streets of value had you bet it out.
If I am the preflop raiser, then I'm leading out at most flops whether or not I hit it. This is partly to take down pots that players do not wish to contest, but also to mask the times I connect solidly with the flop, allowing me to get calls I otherwise would not. Therefore, if you were the preflop raiser, I say you absolutely must lead at these flops. When you flop trips and fire out, a lot of players are not going to give you credit here if they're thinking players, reasoning it was quite difficult to connect with this board. If they are not thinking players, we're back to my original statement, and you should be firing to extract value from any hand they deem is worth a call.
A slowplay could be effective in a few situations however. For example, had your opponnent opened preflop, you flat-call, and are oop (Terrible set of circumstances by the way). Now you flop trips. If leading out is likely to ellicit a fold from the preflop raiser, then checking and letting him take the lead is best. Also if he is very aggressive himself, then check/calling two streets and value betting the river is not a bad line. If he's extremely aggressive though, then betting out may again be best as he may see this as you trying to pry him off his hand, causing him to respond with a raise that may tie him to the pot. This is a very exact set of circumstances that it takes for the slowplay to be better than betting, so please keep this in mind.
About the only time that it's correct to slowplay is when you just crushed the deck. You have AQ and the flop comes AAQ, AQQ, QQQ, AAA. In these scenarios you have all the cards worth having. You have to slowplay in the hopes of letting another player catch up to a second best hand that he feels is worth putting a little more money in the pot with. Again, these are very specific flops, and are the exception, not the rule.