Relief is very easy to check. Simply put on a capo on the first fret, then press the low E string where the neck meets the body. Probably at the 14th. fret. You have now created a straight edge and can measure the gap between the fretboard and the string. If you have two capos use them at both points, it's a lot easier. A feeler gauge will give you an exact reading, but just looking will probably tell you if you have an excessive amount of bow.
"The music business is a cruel and shallow money trench, a long plastic
hallway where thieves and pimps run free, and good men die like dogs.
There's also a negative side."
--Hunter S. Thompson
Guitars: Dean Sweet Wood 00R, Martin D2R, Guild D60, Guild D35NT, Morgan Monroe M30, OS baritone Uke