I've been in the industry for about 10 years. Like I said, it's more about limbering up my brain. I have a good time with it, and usually learn some new things. Memorization is pointless, so I try to solve new and interesting problems rather than re-implementing the same old data structures and algorithms every time.

To be sure, some people take it too far. The "four months" figure does not come from me.

Especially when you have hardly ever had to use it in your 15 years career.