That's not a good metric. Everyone sleeps in their bed for a lot of hours per week but only a subset of people are sensitive to discomfort or back issues.
Why does anyone spend their time coming up with rules for what other people should do in situations that are inherently based on personal values?
If you don't buy a good bed you'll develop back issues.
And actually the majority of sedentary workers will have back issues in their lives so it's even more important.
This rule works for me and since it's not actually straight forward to figure out, I thought it would help others.
...or you could put a lightly padded mat on the floor. The cost is minimal and it makes my back feel healthier than a bed. As far as I can tell, beds are for comfort not health.
Why does anyone spend their time coming up with rules for what other people should do in situations that are inherently based on personal values?