My CF box has a plan set that we build up for three weeks, 3rd week is crush week, then 4th week we taper down and take it easy. Body work, lighter weights, work on form, etc. Currently I work out 3-4 days a week, light cycling in-between as well, and I've really enjoyed this shift. When the next months "week 1" begins I always feel strong and fresh ready to go. The body likes mini-vacations too :)

Although I always want to do more more more, reading Wendler's book finally cemented in my head taking the fourth week off, or going lighter that week. Work hard for 3, rest/go light for 1, repeat.

For me I try to follow the signs my body gives me but on average I take a week off to relax every 4-5 weeks. This is nothing that I plan it just happens naturally, same as my hunger and how much I eat varies.

About once every 4 to 6 weeks I take a few days off. It's refreshing and a nice way to put my workouts in perspective. I usually know it's time when I'm dragging through a run or weight bearing exercises.

Yes, I do about every6 weeks. I tend to wait until my body asks for it though

9 weeks is too long, there should generally be an 'unloading week' of reduced volume about every 4 weeks. That's pretty standard from what I've seen/read/observed, and I think I've also heard Robb say closer to that and not 9 weeks.

I suppose for people training at very high intensities they should back off every 3-4 weeks, while casual fitness people would be fine to take breaks closer to every 9 weeks.

I do take breaks from exercise, but not in a planned manner. I usually take a breaking from working out when we're on vacation. We do a ton of walking (and eating), but I don't do anything intense.