I have acronis also (Acronis is an imaging tool.  I do a clean install, install all patches, drivers and any programs I KNOW I will be using, then run acronis and make an image).  I also do alot of software installs, uninstalls, tests, etc on my laptop.  My laptop probably gets reimaged every 6 months or so.  My desktop sitting in the office, however is running on the same install (no reimages) for the past 3 years.  The desktop is really only used for web-browsing and stuff by my wife.  Acronis saves me hours (reimaging takes....5-10 minutes)