I routinely re-use yeast, by basically pouring the trub from a (New Sachet) brew into a jug and thence into 4-6 250ml bottles (formerly containing lemonade) which go in the fridge. I only ever go one generation down and chuck anything that has been in the fridge longer than a few (3-4) months.
As others have said, I get the yeast bottle out of the fridge early on brew day and chuck the whole lot in. Never had any problem with this approach, but the attenuations I experience are quite high. Could be the mix of yeasts I use - US05, Gervin, Saison, Belgian Abbeye , Wheat etc.
No issues at all, really, though I brew to my own preferences, rather than Competition styles.