There is no definitive answer to this question as it depends on the individual and their specific needs. Some people may prefer to uninstall previous versions of Photoshop in order to keep their software up-to-date, while others may prefer to keep all of their software installed so that they can access it at any time. Ultimately, the decision comes down to personal preference.
WATCH BEFORE Updating Photoshop
Check out Your When You Open An Image In Gimp It Appears As A Layer In Layer Palette?