I save the slurry from most of my batches and will use it over and over again. Haven't had a bad batch yet from one of them, and I let one go to 6 generations before I had a day where I just wanted to clean the fermenters and be done, also ran out of mason jars. I've learned to brew subsequent beers that will benefit from the yeast used in the last one...for example I just kegged an orange wit, saved the yeast, and it will be used next weekend in my first fruit ale. The yeast from the orange wit was a combination of fresh Wyeast Wit yeast and some of my blonde slurry. It took off like crazy within 6 hours and fermented clean. My opinion is, if your beer ferments clean, has no off flavors, and you didn't add loose fruit or hops in the primary, the yeast is fine to save for another batch that may be a completely different style (except for Belgians, sours, and other beers where the yeast is a big determining factor in the end flavor). I used slurry from a jalapeno amber in a Scotch Ale (horrors!) and had absolutely no weird flavors in it.