How often do you reinstall Windows?

[bacon]

I reinstall, on average, every 2 weeks. Mostly cuz the programs I make sometimes do unexpected things.

 

[kannan]

i use to reinstall every 6 months. Generally Windows gets slowdown after installing a lot of software.
Also when the registry size gets larger automatically everything goes slow.

Still i use norton utilities to keep system faster.

But doing a full format and installing Windows keeps system faster.
I am going to do it in another one week.