If I get sick it really screws with my training. I usually even have to back off the weight a bit when I get back even if I’m just out for a week or something.
I don’t really take full weeks off though, just an extra day or two off if I don’t feel ready. Last weeks training was pretty brutal and I had a rugby match yesterday so I’m feeling pretty drained today. Just means I can’t train 'til wednesday and one day off won’t kill me. In fact it means that I get to relax and will probably have a good session when I do get back.