Freelancers, do you usually bill more or less than your work hours?

Ideally you charge for deliverables or outcomes, not for your time.

Does your auto mechanic or plumber or doctor charge by the hour? No, they give you a price for what you need. And they base their price on both market value and their cost (including their time).

Fixed fee for a large project can go wrong badly because early mistakes or missed requirements can set the schedule back and increase the complexity of the work. Break big projects into smaller tasks that you can reliably estimate. Review progress with the customer frequently. Know the business value of your work, not just how long it will take.

Don't bill by the hour. Bill by the week instead and set a day-rate that is 1/3rd of your week rate so you don't get cut into little ribbons by lots of short jobs.

I usually estimate an average amount of hours I can dedicate on the projects a week. Some I strike the limit others(More frequently) while others work less hours

Possibly unhelpful but: I only do fixed-fee projects, which eliminates the need for time tracking. That said? About 15-20% of my projects run longer than budgeted.