2011 2.7 GHz i5 27" iMac on 10.9.5, 12 GB RAM, stock 1 TB WD 7200rpm, about 50% full, mostly video/pics/audio. When new, I used to brag to my PC friends about the 5 sec shut down time and 35 sec boot up and online time. 4 relatively trouble-free years later, I'm shutting down in about 35 sec and booting up and online in about 2:25. Disk Drill / SMART say there is nothing wrong with the HD, and permissions are all in order. If that is the case, then maybe a purge & reinstall is the key to restore earlier performance (of course, it could just be Mavericks too). Assuming however that it is just in need of a cleaning /defrag / reinstall, what is the preferred method to maintain all my data and apps, while losing all the clutter? I run Time Machine, CCC, and Backblaze, but I think those all will back up everything, including the garbage, yes? I've got loads of (legit) software including add-ons, extensions, scripts, etc. that I'm not sure how to corral, plus whatever I've got running with Parallels/Windows. However, as SSD prices continue to drop, e.g. I see the Samsung 840 EVO 1TB for under $400, I'm wondering if it might be easier to just migrate everything from the WD to an SSD (other than the install, of course). But then wouldn't a migration just carry all the fragmentation and cruft with it? The more I read on this topic though, the more confused I get. Any direction is appreciated.