I took an hourly rate at my current job because I was still relatively junior and I didn't really understand the difference between billable time and administrative time. I also didn't find out until too late that we bill down to the minute. My boss actively and aggressively tries to minimize time logged to only 100% billable/productive time, to the point where after I factor out communication and various office tasks I can never really log more than around 4 hours in a day unless I'm working an insane amount. I once woke up at 7am and logged 9 hours of work in a day. I only stopped for meals and I went to bed that night shortly before midnight.
Now I'm completely burnt out after 7 months, and my productivity has dropped drastically over the past few weeks to the point where I'm either calling in sick or actively avoiding my superiors all day. I'm agonizing over whether I should quit first or if I should try to hold on until I find another job (I would've fired me by now). I don't have very much money saved and I have student loans. Plus, my boss has basically destroyed my self confidence. I'll never take hourly pay for this type of work (outside of freelance) again.