When romex is run across rafters in an open unfinished attic it is my position that a raceway of some kind 1x3 s or even 2x4 s should first be attached across the affected rafters perhaps 3 to 4 above the joists then the wiring be stapled to the raceway.
Running wires without attic.
Totally hidden existing knob and tube wiring meets code and we have left it in place inside some interior walls.
But if you have knob and tube running in an attic or exterior wall the space can not be insulated until the wiring is replaced.
Watch the entire process step by step.
On a single story home or the the upper floor of a multiple story home this means accessing your attic to run wire.
If you re working from the attic you can drop a weighted string down wall cavity then attach the wire to the string and pull it through.
The actual install of recessed lights here https youtu be 5yc8aqnvqqg the long bit is actually used.
Attempting the job without preparation and taking the proper precautions can cost you time or money and can even be a serious safety hazard.
You ll need two wires one white and one black for one circuit or more if you intend to wire a three way switch from the house or add more than one circuit.