Electrical K&T retrofit

[Fred]

I'm replacing all my K&T wiring with Romax wiring. When I fish the new Romax in the walls, do I need to staple it to the wood studs every few feet? If so that means I need to tear all the walls out. But all I see are electricians do is fish the wires down to the existing switches or receptacles and make the connections without stapling the Romax to the wood studs, not even within 6" from the boxes - is this ok with NEC? TIA

[RBM]

It's fine when you're fishing it in, but not OK in new construction. BTW "Romex"