This is a question I’ve struggled with a lot myself. From my 15 years of experience as a contractor:
1. Never lower your rate, bringing it back up will be way harder then you might think.
2. Breaks etc. are billable. I even bill for walks that may be a long an hour, as long as I think about work. If I stop doing that I stop the clock too. Like others said, code is just the end result. I will usually produce better if I take a breather. Thinking things through will almost always let you find ways to write less code, resulting in a more stable and maintainable solution. Nothing suggests you think better while seated infront of your screen.
1. Never lower your rate, bringing it back up will be way harder then you might think.
2. Breaks etc. are billable. I even bill for walks that may be a long an hour, as long as I think about work. If I stop doing that I stop the clock too. Like others said, code is just the end result. I will usually produce better if I take a breather. Thinking things through will almost always let you find ways to write less code, resulting in a more stable and maintainable solution. Nothing suggests you think better while seated infront of your screen.
3. Always round up to the next hour.