Wow, that's a lot of personal attacks over someone posting something contrary to your opinion.
Please don't take the response as a personal attack. All views are welcome here, but Mark started the thread to assert why yeast rinsing at the homebrew level is not the preferred route, typically. Since slurry use by direct repitch is so widespread, many of us here follow that approach. Through purely anecdotal evidence, admittedly, following the Denny Conn approach of trying it for yourself and seeing what works best, I simply time my beers to have viable repitch yeast handy from one batch to the next and it has worked great. The greatest number of clean, non-mutated re-pitches for me was in excess of 20. By then, I figured I had stretched my luck and went to a new lab pitch from White Labs. I have stored several months and re-propagated without problems, but frankly I get my money's worth out of a batch if I use it 4-5 times. Also, I rarely make starters any more, opting for small batches that I step up until I get to my desired and typical batch (10 gallons for me).
One thing is for sure - YMMV, so try different things and see what works best for you.
Oh and one further thing to note: Mark uses amateur as a distinction from professional Brewers who brew for a living and likely have lab support to some degree. He is not using it in any pejorative sense.