I strip the wire in traffic jams or when I'm waiting for the inspector. Sometimes just hanging out in the back yard enjoying a beverage, waiting for the steak to cook.
I concentrate on getting the jacket off all the romex first. Then separate the ground (if there is one, a lot of the older stuff I remove from houses have no ground). Then I strip the conductors biggest to smallest. If I don't get to it all and I want to bring it in, I've maximized as much as possible.
For awhile it was roughly $3 for bare copper, $2 for insulated conductors, and $1 for NM still in the sheath cable. Considering the price of romex at the big box stores I'm sure it's gone down a bit since January.