ok i practiced this when I still have my PB...
If i'm going to use my PB in the next 24hr, keep it sleep.
If i'm not going to use it more than 24hr, shut it down.
If i'm not going to use it more than 5days, makesure the battery have 50% charge, shutdown the PB, remove the battery, keep it somewhere dry n not too hot.

I've travel to lot of places with the PB is sleeping in the bag. lol... it even went over the xray scanner.