[butteroverflow]

I see you're using the default prefix (C-b), with C-a being the 'recommended' alternative. I don't understand why it's so popular, as it breaks emacs-style navigation in readline applications, which is great for fixing typos/changing something in one of the previous commands.

I remapped my prefix to C-q. It's a relatively useless key (who needs flow control these days?) and it's close to the number row — you can press it and then quickly get to a number key.

[TeMPOraL]

C-a also breaks Emacs-style navigation in readline applications (jump to beginning of line, a pretty useful function). And of course it breaks navigation in Emacs too (which I frequently use over SSH). C-q is also useful in Emacs, so my tmux is remapped to use C-^ as the prefix key. Nothing useful sits there for other programs, and I personally don't need the tmux prefix often (I do 90% of things straight from Emacs, and it has its own windowing capability).

[sp332]

screen uses ctrl-a, so it was easier for people switching to tmux. Never did figure out why it was chosen for screen back in 1987. Emacs was around for 10 years by then but GNU Readline wouldn't be released for a few years yet.

[graywh]

I use ctrl-_ which is generated by "ctrl 7" or "ctrl /" on the terminal emulators I use (xterm and iTerm.app)