I have had my La Brea sourdough starter going for at least 5 years. I
don't bake with it as often as I used to, so contrary to Nancy Silverton's
book, I don't refresh it as often. It will often go two weeks without
being fed. Before I bake with it, I feed it once or twice and then use her
recipe. It takes a long time to rise; sometimes a full day to double in
bulk, but the flavor is fantastic. It is much more sour. I think whatever
you can do to slow the fermentation down improves the taste.
Hope that helps. So far my neglect hasn't killed my starter, but "results
may vary".
Cindy
"May your harp stay in tune and your bread always rise."