I personally adore snails, and the work they do in keeping an aquarium clean. It's also easy to overlook a baby snail, as when they are first hatched (unless it's a snail that is a livebearer) they are quite small and translucent.
It's up to you, but I think snails are very beneficial in cleaning algae and fish detritus, making for a complete eco-system. (The Amazon Pantanal's ecosystem relies entirely on the Apple Snail! Without it the whole thing would fall apart, it wouldn't be habitable to anything else. No plants, no otters, no caimans.)
As long as you don't over feed (ie, have a lot of food falling to the bottom/remaining uneaten by fish within a few moments (unless it's a bottom feeder, but sinking pellets/other foods should be consumed within a reasonable amount of time, less than a day or so), the snail population will stay small and monitor itself. They're actually a pretty decent way to gauge how clean the tank is, and if you are over-feeding.
Hope that was helpful!