The secret to this is to "know your framing style"! Depending on the age and style of the building. Where I'm at we have three basic types of framing:
Balloon = 1850's - 1900 Vic's and Ed's
Plated = 1900's - present All styles
Remodeled to death = Who knows what's in there!
Some good tools to have:
A roto zip with plaster blades and wood blades. (remember to have lots of them and use the right blade for the material, or you'll burn them out too fast.)
Fishing poles The glow in the dark kind are the best
An inspection mirror, and a fiber optic flash light that can bend inside a hole.
But as for abandoning the K&T, you are supposed to remove it now!
But remember to tell your customer that sheet rock is a lot cheaper than your time!
(But wood work is not...)
