Stored in a paper bag on the counter, 2 days before going stale. The third day you should plan on French Toast.
In plastic in the refrigerator, unless you're freezing it, you'll lose your crust - it will turn soft, but still be usable for up to 3 days, and becomes bird food on the morning of the 4th day.
"Food is our common ground, a universal experience." - James Beard