It is a challenging thing to do, making a profitable ammount of money or chips on a dry board with a set. On one hand if you slowplay you risk being sucked out on and not making any profit or gaining any chips, on the other hand if you lead out you may not get any action and waste a good opportunity to come up in money. You have to look closely at all the variables in play and the players you are playing against. First off, if you are in isolation and its a dry board i would suggest checking or just calling if in position against your opponent. If there are more than one person to the flop i would lead or reraise almost any board just because it is too easy for anyone to hit a backdoor flush or straight with that many people in the hand. They may only turn 10-20% outs but that is much more common than you think so first look at how many people are in the hand. Secondly, think about the player(s) that are in the hand against you, have they been playing aggressively or have they been playing solid/tight? It is a big deal to which they have been doing and if they can be tricked into putting more aggression towards a pot, and more importantly what do they think of you? Do the players in the hand think that you are capable of reraising with nothing? If so go ahead and do it and maybe you will get some action, if they see you as a tight/solid player i would try to slowplay to try to get more value from my set and hope they hit a 2 pair or you can boat the board later in the hand and get much more value, but be careful when slowplaying that you actually have the best hand, like i said its easy to catch backdoor draws especially w 3+ players to the flop. Lastly, are you playing a tournament or are you playing cash. In a cash game im going to be much more likely to protect my set no matter what because that is money in the pot, actual money, im not so worried about the value as i am that i do not want to lose money, plus chances are if you are reraising anything in a cash game you are more likely to take it down, you really dont want to get yourself into a situation where you slowplay in a cash game and end up losing to some awkward obscene draw, and online, believe me, its more likely to happen. If its a tournament and i have a lot of chips behind me then i will more than likely go ahead and slowplay a dry board even if there are 3 or so people in the hand to let them catch up a bit, If my chip stack isnt at risk i can actually let them catch a draw on the turn to get more value from the set. If im average stacked however, im more likely to protect against a few people to the flop and reraise, chances are someone is feeling lucky if there are a few to the flop and they feel they can turn their ace w AK or something, esepcially in low buy ins. The higher the buy in, the more I may slowplay it as well because people are generally playing tighter and more solid. If Im completly lowstacked in a tournament however and desperately need a double up, im going to slowplay it at least to the turn and then probably check raise all in. Especially if its a rainbow flop w no straight draws. Im looking for almost any kind of action and if i can get someone to commit half of my stack to the turn on any draw then i can probably check raise them and they will be getting at least 2-1 on a call and have to try and double me up, of course im probably drawing to 4-1 fav here, but its worth it to try and double up in a tournament if im desperately lowstacked. All of these variables will play a role in flopping a set to a dry board, so pay attention closely to everything goin on around you and good luck in future set mining