How do you know when a neck needs a reset?

[JLS]

High action & low saddle. And/or a "Yamaha" logo on the headstock

[cozycabin]

Originally Posted by JLS

High action & low saddle. And/or a "Yamaha" logo on the headstock

That's funny! I own a lot of yamahas and they don't have tall saddles for sure when you get em set up comfy. Good news is they don't move once there... luckily. hope they read this!

[1Charlie]

If the guitar is not worth a neck reset, a JDL Bridge Doctor may reduce the belly enough to get it playable again. I have done this on three guitars with success.

[s2y]

Originally Posted by JoeCharter

When there's nothing wrong with your saddle or your nut but yet you could still slide in a slice of pizza under your 12th fret.

Especially if it's Chicago deep dish.

[Methos1979]

You can also sometimes see a gap in the neck heel to body area. This is a Martin 000-28EC I had some time back that needed a neck reset and it was probably only 12 years old but they were 12 well-played years.

Neck gap

[Brucebubs]

Everyone has covered it really well.
I had a Taylor 355 12-string.
Played like a dream, nice low action but the saddle was as low as it could go.
It needed a neck reset - not immediately but certainly a little down the line.