Once you've taken what you need, you can see how much time you've got to play. You can always check the time under "keys & rules". In a near future you will be able to transfer the key, should your phone die, or someone else would like to take over the game.
It's important that you return the objects before the time ends, or else we think you might have forgotten, and we will charge you for a rather high amount of money. Reminders will help you though, and you can always contact us if you forgot the time. If the objects are still there, then of course you will get your money back.