So last June, my wife and I found MMM, and realized that our hair was on fire. The balance on my student loans (our only debt at almost 7%) at the time was $30,000. We looked long and hard at our spending and crunched the numbers, coming to the conclusion that we had been living ridiculously - We'd "aggressively" paid off only 25k on this same loan in the prior 3 years, but could very likely knock out the remaining 30k in 6 months.
Since then, we moved closer to work, found a lower rent apartment, got rid of our only (fortunately already mustachian) car, and started seriously budgeting to get rid of all that extra spending. The possibility of a move had us wanting to keep a cash reserve, so while we crossed $0 net worth by our goal of January 1, it took a little longer to knock out the debt completely.
9 months later we've made it. We're both 28 years old, up to 13k net worth, and with zero debt as of today. it is a small 'stache, but given what we've learned, we're looking forward to how much it'll grow in the years to come!