so if you dont play it for a long time the data gets lost or something?
no could'nt be true i checked and it didn't erase and i have'nt used it for 2 years.
Thats not how it is, you see...
The old GBC games (Gold/Silver/Crystal) have an internal battery, this battery can run dry, all you have to do is replace it, but anyway if the battery runs dry it wont save until a new battery is in there.
And the battery can run dry over roughly 6 years
The type of battery is:-
CR2025
or you can have the bigger battery that will run longer and is generaly better, that battery is:-
CR2032
I recomend the second one. Also the battery is inside the cartridge, so yes, you would have to take the cartridge apart, sorry, it would still work if you took it apart, you would just have to be very carefull not to touch or move the wrong things. The battery is fairly noticable as it is surrounded by a yellow insolator.