For me personally on my Windows machine I will do a complete fresh install of Windows and my applications - probably yearly.  On the Mac it may be closer to 2 years.  I'm currently in the process of rebuilding my Mac now and it is definitely not for the faint of heart.  For me personally it makes sure that all of my content is current as when I re-download it I'm assured it has all the latest updates to the figures and other bundles.

This is just my personal taste in order to keep my machine in top performance, after a year or two there is just so much bloatware that accumulates over time.

Shawn McCarthy
www.defyallchallenges.com