I like having a seperate TMUX session per project I’m currently working on. So a numbered list of sessions quickly becomes unhandy.

tmux rename-session `basename $(pwd)`

ctrl-b s and we get this:

(0) + angular-firmafon: 1 windows (attached)
(1) + blog: 3 windows (attached)
(2) + wallboard: 2 windows

Bonus tip: Put bind ^S switch-client -l in your .tmux.conf. Now ctrl-b ctrl-s toggles between the current and last session.