Probably about 25-30 minutes...never really timed it. That is a job that I HATE to rush. As others have said, sometimes it can be difficult to find that tiny bit of beer bottle glass, or the tiny piece of wire that caused the problem. Also, I'm very careful about making sure the tube isn't pinched by the bead, and that the tyre is centered on the rim. Most of my p*******s have been in the dark, on the way to work. This adds the problem of holding a light whilst you work. In my experience, haste makes waste on this job.