[stickman]

how long can you carve before you should strop?
and if you strop frequently will you blade stay sharp forever?

I remember reading somewhere that eventually your blade will get rounded and you will have to reshape and basically start over from scratch.

so far I have been stropping about every 20 min of carving with the same tool and it seems to be holding up well.

one more question .when you strop do you do one swip down and one up or more like a stone where you do 3 swipe down and 3 swipe up?

[mwilleson]

I strop early and often....sometimes it's just an excuse to think. It will help the blade retain it's edge for longer, but eventually I think the blade will need some sharpening.

I usually strop a few times on one side, then over for the same number of strokes, then back, then the other side. No certain rhythm other than even. Two and two or ten and ten or whatever....

I tend to pull the knife towards me because it personally helps me maintain the consistent angle.

To minimize the rounding, keep the blade flat the entire way. Do not roll up at the end of the stroke.

[Deepwoods]

Sitckman-
mwilleson is right, keep your blade flat as possible when stropping. This will keep your blade from rounding over or developing shoulders. I was taught to strop as though you are trying to smear the last bit of peanut butter over the entire piece of toast.
I know a swedish spoon carver who claims that he has never had to take a stone to his carving knife. When asked how he achieved this he said that if his knife is not in his hand it is in its sheath. (protect your edge) and carve clean wood (don't try and carve after you've started sanding, the left over grit from the sand paper will abrade on your edge)
Carve on!