How long do tortillas last outside the fridge?!

If they start fresh from the store and kept in a sealed pack they should last 5 days. If they do get stale you can lightly steam or nuke for 10 sec.

I treat bread and rolls and tortillas the same way: if they were refrigerated at the store, they go in the fridge when I come home. If they were not refrigerated, I keep them out until I use them. Then leftovers go in the fridge. Check the date on the package. Tortillas are one of those things where the date is a very good indicator as to when the quality will start to deteriorate. In the winter, when the place is cooler, I've had no problem keeping tortillas at room temperature for a week, but it summer, they can turn quickly. Just check for white or black mold and discard any that have been affected