Trust can be good, but the patterns of the past show that your trust is misplaced.
1. You are using Photoshop CS5. This is no longer supported. If there is a problem, it will be fixed in Photoshop CC.2014 and probably nothing else.
2. Apple have, without hesitation, taken away things needed to run old software, or caused it to break. For example, no product made before 2005 (and not updated) can run on any modern Mac OS made since 2011 (unless the product is updated). So, in 6 years Apple can take a product from "state of the art" to "obsolete, cannot run". I'm not saying this is good or bad, but it's certainly something to bear in mind when upgrading a Mac OS that contains old apps. CS5 is four and a half years old.