How long will a sourdough starter last between feedings? I'm using a sourdough starter from the recipe in Peter Reinhart's Artisan Breads Every Day and I have gone through several of the rebuilding cycles with it.  It's been working fairly well for me and I have been refreshing it every week.  It is stored in an airtight container in the fridge.

How long can the starter be left in the fridge without being refreshed before it's un-salvageable and would need to be thrown out?
The following is paraphrased from Andrew Whitley's excellent book Bread Matters

Wheat leaven


If you intend to use within 2 days, store the it at ambient temperature
For 2-14 days, store it in the fridge. Optionally refresh it before use.
For longer, refresh then freeze. Refresh again after thawing.


Rye sourdough


0-3 days -- ambient temperature
3-30 days -- fridge, no need to refresh
Longer -- refresh then freeze. Refresh again after thawing.


Whitley describes "constructive neglect". He keeps a rye sourdough in his fridge that's several months old, so that he can demonstrate to students how easily he can take 50g of it and produce a lovely sourdough from it within 16 hours.

It's a great book.