I have some wires that were originally pulled through a wall from a junction box to an outlet. The drywall is off the wall right now and I'm doing some work on the wiring. Would best practice be to staple the wires inside the wall or is that going to make it harder for someone in the future to replace the wire in the wall?
Wiring is stapled or otherwise fastened to protect it from damage, such as from fasteners used to hang decorations on the wall. You should staple per NEC guidelines. In your case, it's probably a matter of fastening to studs within a foot of each box.
If you anticipate needing to reconfigure the wiring later, run conduit accordingly.
Staples also help stop fire. The vinyl sheath on NM cable burns, but staples will stop it. Jan 3, 2017 at 9:22
I've heard that a few times here, but I've never encountered a documented source for that claim. I'd appreciate any you might have. Jan 3, 2017 at 14:02
Old electricians seeing burned wire sheathing multiple times over the years that stopped right at the staples. Jan 3, 2017 at 14:04
Again, that's what they say. I'd like to hear it from the horse's mouth (and, even better, from some testing agency). Jan 3, 2017 at 14:06
I have. Just keep on putting the staples where they're supposed to go and it'll be covered either way. ;-) Or, nail up a length of typical vinyl-sheathed NM with some staples, light one end on fire and watch the fire stop at the staples. Jan 3, 2017 at 14:07
The junction box is required to be accessible via a plate cover and the wires are required to be secured within 12" of the outlet; both per NEC.
2Since the wire was installed with the wall closed, it did not need to be attached - there is a blanket exception permitting fished wires to float. Now that the wall is open, it's probably a good idea to fasten it.– EcnerwalJan 1, 2017 at 20:15