The process of changing keys on songs I learned whilst my guitar was tuned down a full step continues. Got half a dozen or so done, and it has been a good exercise. Still slow going -- I don't know those progressions well enough so I can do them without thinking.
A recap for those wondering what I'm talking about: For the last few years I have kept my guitar tuned down from standard. (Standard tuning, the open strings are, from bass to treble, E, A, D, G, B, E. The tuning I had gotten used to using was D, G, C, F, A, D.)
The reason for the new arrangements is that when I started jamming with other players, either I had to be in tune with them, or shift chords on the fly. If I was playing a G-shape, it was actually an F-chord, so even though the music is mostly simple, I have to do it for each song.
Either that or use a capo, a mechanical device which barres a fret and raises the pitch. Capo up two, and you are in standard tuning. Problem there is that a capo swipes a couple of useful frets, and it invariably causes strings to go sharp or flat, requiring re-tuning.
In standard tuning, many of the songs I learned while down a step have high notes I could barely reach then; tuned up, I can't get there.
The new arrangements aren't hard to do -- the ratio is the same between chords, save for some sharps and flats along the way -- so if you want to go from playing something in D to playing it in C, you just drop each chord a letter. Between some of them, you have to add a sharp or a flat (half-step), depending on the key, because of how music works on a guitar.
I can sing comfortably in several keys, depending on the song. If I could manage them with the low tuning, I can still manage 'em by dropping the chords a full step. This causes some problems, in that some keys require finger-busting positions. Easy, major chord progressions in, say, C, need different fingering to do them in B-flat, even with barres.
Same words, same rhythm, but if you have been playing it one way for several years and you change it to another way, there's a reset button that's got to be pushed a time or twelve.
(There's a whole other post I could do on this learning-a-new-way biz. I've spoken to it in martial arts discussions, when you are presented something new, for instance, at a seminar, that doesn't work with what you already know. Holds true for all kinds of activities. Not to say you can't learn a new trick, but that if you are an old dog, it's harder because if you want to do it, you might have to un-learn an old trick first. Sometimes, it might be worth it. Sometimes, it won't be. You have to decide if it is or isn't.)
Fingerpicking notes on the fretboard adds another level of complexity. The strings you pick in an open chord in first position aren't the same for that chord six or eight frets up the neck; nor are they the same from key to key, even in the same position.
Ah, well. Just like everything else in my life, it's a work in progress ...