Maximum Rest

Except from injuries, what is the maximum rest one should take from the sport before it becomes detrimental?

I've read about guys taking a few months totally off then coming back mega strong. Whether this is just psychological, or due to them healing up old injuries it's hard to say.

I had three weeks away once and came back feeling mega, conversely I had a week off training which took me 2 months to make up, life's weird like that!

I've had almost 2 months off and I am feeling good for it, no pain in either arm - which is a first for a long time and I watching a steady improvement in all my weights. Maybe because I am doing more?

Interesting, obviously it's going to vary from 1 individual to another, but i would think there's got to be a general guideline.