The battery does not need to be on the charger continuously. I usually charge-up mine for an hour or two at a time while I am in the garage and if voltage drops below 12.75 or so. Once or twice a week for an hour or two is enough to keep the battery at top condition. I do that whether I use the bike daily or not since our charging systems are less than perfect.
On the other hand, if the bike is not going to move for several weeks, then removing the battery from the bike is a no brainer and not a hassle either.