@mhoye @sunguramy ... You can stop and rest at any time but hanging in a harness can get uncomfortable after a time.
You can have a third clamp on the inside of one ankle so that feet can work independently. I found this fast and efficient.
The process is quickly mastered. Only tricky if you need to switch from ascent to descent (or vice versa) when free-hanging. Get it right - easy, a little wrong - tiring, very wrong - potentially fatal.

petzl.com/GB/en/Sport/Ascender