Why accept a 20% pay cut? Let's say you are training for for the olympics, caring for a relative, volunteering for an organization, or something similar, just

Why accept a 20% pay cut? Let's say you are training for for the olympics, caring for a relative, volunteering for an organization, or something similar, just make your availability 4 days per week. If your time is structured, you aren't "off" on fridays, you're busy.