Every horology fan needs one of these
Bergeon 6767-F – Instruments for Clock – an absolute belter of a tool that doesn’t bend, snap or ship under moral usage. Much much much better than the ones given for free with new straps (particularly from China) that can chip, bend and, ultimately, scratch your timepiece.
Summary An epic tool. When either side gets worn or broken, simply order a spare screw-in replacement.