To revive this for a new generation, lol. I used to do about 5 re-pitches with 1056 (US 05), 1214, s-04, Nottingham, and saison yeasts with no problems. With wb-06, 3 seemed to be the safe limit before unpredictability. Last few years tho, I just buy US-05 (1056) and s-04 from Fermentis, by the 500g brick. Sometimes I re-pitch, but not usually more than once, as I don't brew too often anymore.