Any time we are dealt a small pair, it hurts to not take it to the flop. You just have to see if you are going to make your set or not, as when you do it often means you have a lock down on the poker hand. Because the odds of making a set on the flop from a pair are only 1 in 8.5, though, this means that 7 out of 8 times you go to the flop with that small pair, you will see at least two over cards come down, and no set.
This makes it hard for these sets to make it worthwhile, if you are playing out of the odds that you would play other poker hands. Yes, it’s tempting to call a raise and a reraise with threes knowing that if you do hit that three you might conceivably get paid off by both of the others players. But more often you are going to miss the set, and some amount of the time when you do hit it, everyone will fold to your bet.
In no limit poker online, then, limiting yourself to seeing flops with those small pairs down to situations where you getting better than 7 to 1 on your money, or that you can take the lead with the betting and thus pick up the advantage of aggressing your way to winning the pot, you will end up often going broke before that 1 in 8.5 chance has time to come through. Use your odds.