Aircompressor Maintenance

[maxair45]

I did go threw with what I planned and bought the aircompressor from HF. I love it(a bit nosity but you get used to it)! Great for blowing stuff off and i'll be getting an airbrush soon so i'll run it through its paces there but I did run into a question. After i'm done using the aircompressor there is a air presser release valve I can open and it'll release all the built up air I still have compressed. Should I leave the tank pressurized with air in it or should I empty it out?

Thanks