I had a question for the more technically skilled members her. I installed Yosemite and everything went fine, but I just remembered that a few years ago when I had issues with Lion, Apple Care phone support told me that after every major update (even incremental ones like from 10.10 to 10.10.1) you should do a PRAM reset. That seems unnecessary unless you're actually having trouble. Was this advice really helpful? They also told me to occasionally boot in safe mode to clear system caches, which again seems unnecessary. I have very low expectations from their phone support, but I was wondering if there was any validity to these suggestions.