We had some years, in the past, with credit card debt hanging over our heads. Some of this debt came from our adoption expenses (which we were told would receive relief from the government at the end of the process, but that turned out to be a tax credit that we didn't made enough money to claim). Through the sale of a home and its equity, we were able to finally be free from our debt...and vowed to try to never have it again (other than a mortgage).
We buy cars that we afford. We often eat pancakes for dinner, when it gets close to grocery day. We buy our furniture via Craigslist. These are not practices indicative of our spending fast status...it's just the way we do things. But...they might be practices others could use to make a spending fast work.
I think the first time I heard about someone really doing this as a year long challenge was when Tif Fussell (aka Dottie Angel) pledged to buy nothing new for a year in 2009. I still remember some of her stories of the ingenuity employed and the luck encountered that year. More recently Julie has been doing a buy-nothing-new year and has some amazing stories as well. I respect + admire these ladies and other fasters like them so much!
For more on the spending fast check out Debt-free Living by Anna Newell Jones (from the library, of course)...or Anna's blog (via Heather).
P.S. Be sure to read Celia's comment about doing a "free week"! So fun + inspiring!!