Had a summer job as a customer service agent for a big company, and pretty much did work 8 hours non stop, the phones were ringing constantly. I had two 5 minute breaks that I could take whenever and one 20 minute break that I had to take at a set time. The break time wasn’t payed, so you ended up having to be there for 8.5 hours. It was very stressful, but it kinda helped that every customer had a new problem, so it wasn’t very repetitive.
Now I some days take longer and other days shorter, to accomplish from home what I could’ve gotten done working from the office.