I take pretty much every Friday for myself no matter how much client work is happening. Most Friday’s are spent screencasting and learning new things, because we all need time to practice. Then the afternoon is a bike ride with a stop at a local coffee shop.
On top of that I’ve been known to read stories to my daughter after lunch and watch her ride her bike for a while.
I generally get up from my desk every hour and refill my beverage of choice (2 coffees then water all day) and maybe even look out the window for a bit.
I do all of this because it makes me more productive.
You’re the freelancer -> you’re the boss
The fact that you spent 10 hours at your desk yesterday doesn’t mean that you’re more successful then someone like me that is only ‘in the office’ 7 hours a day and at their desk 6.
It may not even mean that you get any more billable hours in the day than I do. My average billable day is 4 - 5 hours 4 days a week. If you’re working 10 hour days it’s likely that you’re only really getting 6 hours of productive work done and wasting 4 hours a day.
Outside of the rare crazy deadline (which I hear all about but I think is a product of not saying NO enough) you should not be spending 10 hours at your desk.
If you are all you’re doing is heading for burnout. I’d like to think that you really want to build a long term successful business - but I could be wrong.