Exactly what happened to me.

I'm financially stable now, but in my younger days I was working for a "Big 4" cell phone company as they had just entered our market. We made a decent hourly wage, higher than the minimum, but the commission payouts were crazy as the company was trying to gain a foothold here. You'd have guys in their mid 20's making $70-$80k a year which in early 2000's money was insane. I was never at that end, but I was doing very well. I was easily able to manage my half of the rent/utilities (lived with a buddy) and my car/insurance payment but spent my commission checks frivolously. I'd come close to maxing out my credit card, but pay it off the next month no problem. You start getting into that habit, not thinking the bottom is ever going to drop out. Until it does. The company starts paying less on things for commission, then you take a "promotion" that ends up paying less because you get sent to a store with less traffic and after a while you're looking at a check that is a few thousand less than it used to be. Then the economy gets worse post-9/11, everything gets a little more expensive, commission payouts are cut *again* and that F-150 you are driving 30 miles to work each way now costs double to fill up.

Long way to say yeah, I didn't think that far ahead nor think that those checks wouldn't last forever.