Well when you think of snails in the long term they are very helpful they eat algae if you ever get an algae bloom, they eat dead plants decreasing nitrates and are a treat to your fishes . That doesnt mean all fishes will hunt them down and eat them but it is control. All you can do is control them like add a ram or a puffer or a couple assassin snails or manually remove them.
Depends on the species, quite a few snail species eat live plants, I had an infestation of those, got a couple clown loaches and my problem was solved. Plus, they leave Malaysian trumpet snails alone, which I now have a nice healthy population of. Sweet deal!