Updating to Craft 4.5 requires no more work or prep than any other Craft update. Make a git branch, test it locally, back up your database, etc.
If you have projects still running Craft 3 and the new features in Craft 4.5 are pushing you toward upgrading, right now is an excellent time to do that work! I recommend these two steps for upgrading a project from Craft 3 to Craft 4: