In reply to gaz_jones: I think 8's the most I've used on a route(up to 25m, sunday sport area), then +1/2 for clipping to lower offs... the one multi-pitch I did (by accident) only needed about 6 per pitch with a very obvious bolted belay out to the left of the route itself. 8 should be enough, but I take 10 on the lines that are heavily bolted.
