As far as I'm aware, you're allowed them for 24 hours and then they must be deleted, unless you own the actual cartridge. As was the case with Fire Red xP

I prefered playing Silver on the PC instead of the game boy, myself, as it's more comfortable for me to play using a keyboard and monitor instead of the GBA.

I've not played any of the console Pokemon games other than Pokemon Stadium, which was quite fun with friends, and of course with them, it wouldn't be a problem like with the GB games.