Do any of you grill gurus keep a spare propane tank at home? I just have the one tank that goes with my grill, but there is no way to check the propane level of the tank, so when it runs out I'm usually in the middle of grilling something (last night it was turkey sausage which I had to finish under the broiler). Does anyone keep an extra propane tank at home, or do you just take your one to get refilled before it actually runs out? I figure for 30 measly bucks, I might just buy a spare tank.