Why do so many NFL players go bankrupt?

[SirClintonPortis]

Originally Posted by Schneed10

Can you explain to me why it takes knowledge, or intelligence, or whatever to protect yourself from spending all your money??

Because my 3 year old is capable of looking in her piggy bank and counting how many quarters she has, and whether she has enough to buy a Dora doll.

Because humans rarely are perfectly rational in how they behave and thus what appears self-evident to some people does not necessarily make it the norm. The pheonomenon appears prevalent enough to warrant serious attention.
Hyperbolic discounting - Wikipedia, the free encyclopedia

Considering that people like to run up debt on their credit cards and the like, it's safe to say that there's at least some biological influence on why they keep spending even if they know they won't balance their budget. Woefully irrational, but that's exactly why "knowledge" is needed to keep said influences in check. Not everyone's a Leopold Mozart who knows how to manage their money well with little outside help. Some are more like Wolfgang and prefer gratification over disciplined spending.