I have a 3 year old Macbook Pro, 2GHz Core Duo, 2gb RAM. It's been running Tiger since day 1. Lots of apps, docs, installs, uninstalls, etc...I did an upgrade to SL and all is fine. But wondering, after 3 years of use, would I be better of wiping the hard drive and starting from scratch with SL? Like I said, so far, everything seems fine. But nothing is really much faster that I can tell.