I have GMed many campaigns, both regular tabletop and here on Roll20. I do try to save pages, because you never know when the players might want to go back to a previously visited location. The longest Roll20 campaign I've run has been going for nearly a year and is still running. As for general advice on long-term campaigns: The biggest problem I've run into is having players drop out for various reasons, usually school or work-related. Sometimes it happens with no notice. I would definitely advise you to be prepared for player dropouts, and think on how to introduce new players to a currently running game. Also, if you're going to have a game that goes on for a long time, you will definitely want to put tags on different character sheets so that you don't have to scroll through dozens of names when looking for a certain sheet. I usually group them by category or faction so I can search the tag and get a shorter list of characters. Depending on how heavily you use maps, definitely try to have some generic maps made up in case the players decide to go somewhere unexpected. Generic terrain type maps (forest, desert, cave, city street) and location maps (bar, starport, hotel) are very handy. I love talking with people about RPGs and GMing, so feel free to PM me if you ever just want to discuss different ideas!
