Wow. I am in the minority here, but zipper first! Hold the button and button hole together in one hand, zip up, and then button! Always!

Button first. Reduces stress on the zipper. Nobody wants premature zipper failure.

Tuck in undershirt, button, buckle belt. Do things for a couple hours. Wife tells me my pants are unzipped again

I leave them both open for ventilation.

Button first, then zipper, then put on pants.

Zip, then button

https://youtu.be/TlZXxwsmLdE?t=19

Was someone watching the first season of Babylon 5?

Button then zip

Zipper.

If they are loose enough sometimes I do the zipper first, otherwise I do the button first to make the zipping easier.

That’s a good question for which I don’t know the answer, even though I do it quite often. 🤯