If you are planning to eat your pie today you can go ahead and keep it out of the fridge in a cool, dry place. If you are going to eat it tomorrow or a few days from now, just put it in the fridge. Fruit pies will last about a week and custard based pies will last 4-5 Days.
If you decide to serve your pie warm put it in the oven at 300 for 10 minutes or so.
1.Wrap you pie completely in plastic wrap or seal it in an airtight freezer bag and place it in the freezer.