UBI in the 2010s, 4 10s in the late 2000s. These things never stick. 5 8s is a great compromise between employers and employees. Every time someone tries something different they decide they don't like it, either the employer or the employee.

My employer hired me for 4 tens. I felt like a zombie during the week. I'd much rather have a few extra hours every day than a Friday to myself, especially since I need to go into the office on Friday's occasional anyways. I moved back to 5 8s.