The one you pulled out and sold, was it working your bike before you tossed it into the drawer? The fob is just a transmitter with a hard coded number that it transmits to the bike unit. The bike unit is what you are programming when you do the procedure so that it remembers the code and the codes of up to 2 more fobs at the same time. The fob will transmit the same signal no matter how long the battery is out of it. The bike should remember that fob no matter how long it goes without using it if it has been programmed into the bike unit's memory to start with.Pull your battery out of yours and let it sit for a few days. I just sold one to a fellow member here. I never use them. I pull the batteriess out of them, toss em in the tool box. The one "remote" I just sold to a fellow member here a few weeks ago had been in the tool box for months. I tossed in a battery and no go! Had to reprogram it to make sure it was a good one before shipping it to the fellow member.
Now your right if you catch em with a low battery and just do a change out, but if a guy loses his battery at say the begining of winter and that remote sets for months, it will need reprogramed. That is what I have found to be the case.