FWIW I used to perform a regular ritual of maintenance routines including volume structure checks, surface scans, permission repair, file defragmentation, volume defragmentation, log rotation, etc., etc., etc. but over the years I have slowly abandoned all of that and my systems are more stable and run better and faster than ever. (The Keychain problem I mentioned earlier was, my own fault and related to a series of changes I was making attendant to converting/upgrading the 1.1 TB Fusion Drive in my Mac mini into separate 1TB SSD and HDs and not a maintenance or system glitch.)
I still do most of those tasks (don't know what "log rotation" is, but I do use Onyx to delete some logs), and both of my Macs always run "lean, clean, and mean". Given that both of my Macs now have SSDs (not hybrid drives), Volume Optimization is not longer applicable, nor recommended. I do though still use TechTool Pro to perform File Optimization.
