Question...

Your best guess: what percentage of airline pilots wear the shoulder harness the entire flight?

Is it fair to say the shoulder harness is released on climb before 5,000' by most pilots?
And that is put back on descending through FL180 (and usually on NLT 10,000)?

Thanks.

Entire flight?? Maybe some super short flights done at regionals, but that’s probably low single digit % of all flights

5000’? As soon as the gear comes up it’s a race to see who can unclick the shoulder straps first.

on descent usually between FL180 and 10,000ft.

I click mine off during the reach for the gear handle

I usually wait till cruise.

What is the purpose of shoulder harnesses? To stop forward momentum in a crash. So therefore once I am away from the ground there is no reason to protect me from forward momentum. So usually 10,000 feet is when I release my shoulder harnesses.

Someone is having a fun trip.

Good luck putting your shoulder belt back on after an engine blows at low altitude with an emergency return to the airport.
Or a trim runaway...

Delta- voice : Did you run the QRH?

Regional - voice : Nah, I was too busy putting my shoulder belts back on.

Should have plenty of time to buckle up while you get vectored and run your checklists...

Gear retraction: Shoulder harness.
10,000ft: Cover every square inch of window/windscreen with shades.
18,000: Headset.
TOC: Study anything "flight related."

Whatever it says in my FOM.