My 2007 MacBook Pro is, obviously, long in the tooth. Going on 6 years this summer since I entered the Apple fold, it's done well. And while it's far slower than current hardware, my home needs have become very modest and the iPhone and iPad have become my latest computer upgrades. So, like my 2004 Honda Accord, I'd rather change the oil regularly and try and get 200k miles from this laptop instead of buying a new Mac right now. (And to that end, I replaced the stock 160GB drive with a 500GB two years ago, and replaced a failed fan, spending $30 instead of $1300 to replace the computer.) But perhaps you've experienced the cruftiness of old Windows machines? Conventional wisdom was that a Windows 95/98/XP machine needed to be wiped and reinstalled every two years, because the accumulated gunk of system upgrades and software installs and deletions, ultimatley bogged the system down to where you were better off starting fresh. I experience that and did a number of from-zero Windows reinstalls. The reality is, Apple computers suffer this as well, though maybe over a slower time scale. I've taken this machine from 10.4 Jaguar to 10.8 Mountain Lion over five years by install-in-place system upgrades. I've added and removed numerous apps; tried and discarded various utilities and haxies; and transitioned the computer into its third household LAN. The past year I've had a number of bit-rot problems, with settings not remaining set, chronic dropping of a USB drive and exasperating iTunes synching problems. I've reinstalled twice the past year, but each time I used Migration Assistant to bring all my data back from my SuperDuper! backup. For fear of losing personal data, itunes metadata, and iMovie settings, I've basically reinstalled the bitrot everytime. But my problems are getting worse, my annoyance with the computer increasing; but I don't want to buy a new computer right now. Stepping back and taking a breath, I concluded I had little data at risk.My personal data is in my Documents folder. Photos, music, movies -- give or take some settings -- are obviously stored in their respective media folders. iCloud now has Calendar data and bits stored online. My iphone and ipad are synched and have duplicates of the key metadata, so I should be able to synch backwards and recover everything. So I'm doing a nuke-from-orbit, reinstalling with Migration Assistant, and hoping heal the addled brain of my MBP, and maintain all important data and metadata. But what I've learned over the years is that everytime I do something like this, I wish I had a few notes from the last time to help along. So here will be a few notes for me to find and help out when I do this again in a year Maybe it will help you a little.