Comment by carodgers

I've hit this problem multiple times. The approach which finally eased this pain point for me was to take care to not overwrite any tmux defaults with my config, and only add non-conflicting configs (new shortcuts, styling changes, etc.) That way, if I need to use tmux on a new or unfamiliar machine, the core functionality is still present, and I just miss the candy that comes with customization.

For example, leave the existing prefix binding (ctrl-b), but also add something nicer for day-to-day use (ctrl-space or similar).