Snails are hermaphrodites and thus can self-fertilize their eggs. If you have fish in there, they will likely get eaten by the fish. If not, they tend to require quite specific conditions for them to hatch successfully, though it does happen, and yes they can, in the right conditions, take over your tank, but if you have any clown loaches or a plec etc, you should be fine. If you have any carp varieties (goldfish, sharks etc) this can help as well, as they tend to consume the eggs, and also anything living that they can fit in their mouths lol. You should be cleaning the gravel at water changes using a python, this will also hamper the ability of the snails to breed too much.
I find quite a few snails in my filter, but not many in the tank itself. The one thing you have to careful of, is if they do breed excessively, they excrete like any other animal, and consume oxygen, so can damage the environment around them. Trumpet snails are the ones to watch for, rather than rosy snails.
However, providing your tank is well filtered and aerated, and you maintain regular water changes, unless you see lots of snails slithering around, I wouldn't worry about it too much.