Game servers for SA-MP, FiveM, VC-MP and Liberty Unleashed

I'm afraid to save my cars to a house in case it expires and the car is lost forever. I didn't lose anything yet, but would be nice to know ahead of time if I can get those cars back, like in case of garages.

I know that one person can't have two accounts on the server. So what is the policy for two people in the same household playing on the server? I would like to bring my sister on, that would be separate computers but same internet.