I only customized tmux once, and that was just for fun to change the colors at a previous job to match the branding on some of our servers.

Other than that, I always use the default CTRL+B (MOD) and rarely if ever do anything other than the following:

- MOD + d to detach, "tmux a" to attach

- MOD + c to create new window

- MOD + % to create new split pane, " for horizontal

- MOD + space to change between pane layouts

- MOD + pgup to scroll in buffer