On going maintenance I use 3 apps routinely
For system I use these about every month
Cocktail, this cleans out all the caches and logs (think it is about $30 download)
Diskwarrior, rebuilds finder directory
For FCP
Preference Manger (same people that make FCS Remover) both are must have apps.
For new installs always clone your existing drive, that way there is no risk. Then reform your system drive and update system, than FCS, update that, then install current drivers and other software.