Are you sending the emails directly yourself? If so, that's your first mistake... it's not just about staying off a list, getting whitelisted is hugely important these days too. Work with a provider with a history, stable addresses and good relationships.
As far as bounces, there's no magical way to forecast a good address although some people will try to connect to each address up front. Instead why not consider triming the length of your list? Someone who signed up 2 years ago and hasn't been emailed since is really not a part of your database at this point. Focus on the more recent members and start removing the bad names up front to avoid this issue down the road.