Thumbs up! (Or not)

Tannin

ON ACOUSTIC GUITARS, YOU - 

* A: Never use your thumb to fret notes
* B: Seldom use your thumb, but once in a while, yes.
* C: Your thumb is an established part of your fretting technique, though in a limited way
* D; Habitually use your thumb to fret notes 
* E: Use your thumb a great deal; and it is highly mobile (you can reach several different strings and frets with it without impact on what you are doing with your fingers).

(Acoustic players only please - electric guitars are obviously a different thing with narrower necks and lighter strings; they are more "thumb-friendly".)

Tannin

I'm a C, but just barely. After nearly 50 years as a firm A, I've been working to expand my palette a bit and I've just about transitioned from B to C. I doubt that these old hands will ever take me to a D, but you never know. 

enjo

C/D - all barre chords with a root on the low E are fretted with my thumb.

TTony

B

But I use it more to kill the E string when I don't want it sounding.

sev112

B or C

munckee

C I guess if I was playing D/F or Am/G open and   I would use my thumb or F shaped barre chords 

maltingsaudio

C/D to make it work and easior on the wrist for me.
Slightly off topic but realised my chord fingering has changed a lot over the years as I’ve built up strength in my little finger .  

ICBM

A

Kilgore

A

tomjax

C/D - if you play much fingerpicking blues stuff its almost essential.

fastonebaz

B  mainly just for F chords

Dave_Mc

I'm a C but I'm mainly an electric player.

guitarjack66

A. Because my hands can't reach. And I like wider necks than standard,if able to get them.

stickyfiddle

C/D depending on what I'm playing. But it's definitely a part of efficient guitar playing, regardless of acoustic vs electric imo

Tannin

^ Wow! Step outside and say that to a classical player!

drofluf

B, but I’m seeking help

DavidR

Lifetime D! :-)

You just can't play many/most Blues and Ragtime pieces anywhere near as easily without this being a staple of your technique. Only E string. And, come to think of it, only F shape chords. Play barred F shapes too if piece is easier to do that. I can play a complete F shape across all strings either way. Although, when hooking over, I will sometimes not hold down the A string of a full F shape with my ring finger if the piece does not require it. But if it does, I will move my ring finger to that string and hold the D string down with my little finger instead.

And only on acoustics not classicals obviously. As an aside, one thing I have never picked up is the experienced classical players ability to play the base strings with their index finger. I'm sure it's not that difficult a habit to acquire and probably just needs a piece which requires it and which would force you into that hand shape. I always thinks it look impressive! Does it cause hand strain?

 As regards use of the thumb as per OP @Tannin ;, I just do it automatically now at 67. And I think if you persist it ain't that difficult folks! Assuming you have hands which will make these shapes without hurting. In which case you should avoid to avoid injury.

Tannin

^ I never, ever did it. Then a few years ago I went at it like a bull at a gate, pushed through the pain barrier (no pain no gain!), and very quickly ran into injury problems. They healed after enough complete rest. 

Since then I've been sneaking up on the thumb thing slowly, very, very gradually doing a little bit more and a little bit more. But I wouldn't dream of fretting anything with my thumb if a nice, easy barre chord is a practical alternative. I only use the thumb when there isn't any practical way to play something without it, almost always just for a passing note in a run under a chord. And only ever on the E string. 

I have medium-large hands (which should make it easy) but I also tend to maintain a more technically correct wrist position than most rock players (not all the time but mostly). Rock players tend to have the wrist high and the thumb well above the top of the neck, and thus their fingers fairly parallel to the surface of the fretboard. Classical players aim to have the wrist low, the thumb behind the neck, and the fingers more-or-less at right angles to the fretboard surface.

So to use my thumb, I need to lift my elbow and de-rotate my wrist a bit, which is awkward. Otherwise, I end up with a clumsy death-grip and way too much tension in my wrist and hand. 

A smaller neck would make it much easier! On the other hand, thinner necks have so many other disadvantages that this isn't something I would consider. 

p90fool

Somewhere between D and E. I use my thumb all the time, it's the basis for everything for me in that I always have a root note available wherever I am. 

For example I play an F#maj7 where the thumb plays fret 2 on the 6th string 
1  6
2  6
3  6
4  4
5  x
6  2



I could just play a conventional F#maj7 but I like the addition of the higher voicing. I apply it to lots of different chords all over the neck, but I do have pretty big hands. (The pictured Loar LH300 has a huuuge neck btw)

Soupman

Nah, I'm definitely an A. 
When I started learning chords I persevered with barre chords, the logic being: that way it didn't matter which strings I clouted (thrashed) they should sound ok!
My thumb never frets, just mutes the low E.

Supportact

B for me. Very occasionally. I will more often use the thumb to dampen the E string while playing open chords though, rather than actually fretting a note.