I really need one or two rest days a week. Given that I get at least four days bike commuting, it means that two of my three weekend days are rest days.
If I don't take my rest days, I begin to drag during the next week, then by the following weekend, I'm pretty much inert.
It's been that way for years, so I just plan accordingly. I make the most out of my commutes during the week, and carefully choose my weekend rides.
This time of year, a typical week is 30 miles a day commuting (which isn't bad for a nine-mile round trip). Friday is almost always a rest day, although I will ride to the bank and the grocery store--a 5-mile loop which I don't really count. I do a 50-70 mile ride with the club on the weekend. If I do the Saturday club ride, I'll maybe do a shorter, lighter, recovery ride on Sunday. If I do the Sunday ride, then Saturday is usually another rest day.
It gets me 170-210 miles a week.