Never Update: Most of my clients are Mumbai knowns freelancers web developer, photographer, knowns music editor, short movie makers, etc I always ask my clients to never update their Operating System if they are in a middle of any project which is going around, as for any reason if the update failed they will have a non-working machine which may impact their work.
Data Backup: Data is very important, a damaged MacBook can be repaired but once a data is lost it required lots of effort, time and money to get the data recovery so before updating Catalina make sure you backup the data you can do manually backup by copy-paste in external drive and in case if you are using apple mail or outlook for email I will recommend you for “time machine backup” make sure the hard drive has enough storage also try to use a blank hard drive for data backup.
64Bit OS: The new macOS Catalina is 64Bit Operating System and there are still lot of app developers that haven’t updated their software yet, so make sure check that apps you will use must have compatibility with the macOS 10.15 you can find this easily by searching on their website, forum and of course u can drop a text I will find that for you.
You must know:If you are DJ or has anything to do with iTunes do not update, as Catina does not have iTunes as its directories have been changed a lot which is required for DJ software.
Beta Version: Never update beta version as it is for the people like me who will test and report it to apple about the bug if your machine is for production work use for that instead of becoming a beta tester as many a time the beta version crash lot and you will have to wait for the long till they release new update as a fix for that bug. Once I had to wait for 14 days to get the safari working after updates so say no to beta version let the people use and test. The best practice is to keep you machine one version behind example right now the latest version is 10.15.3 (This is beta when I’m writing this blog) so keep your device to 10.15.2 or 10.15.1
Why Update: Do u really want that update or your operating systems. My personal MacBook Air still running on 10.11 [El Captain] as the work I do can be done on it without any hassle so I have turned off the update and never turned back on [If you want to know how to turn off update u can drop me a what’s app I will guide it 3 simple steps] yes the machine I use for business I keep it updated as I have to test all apps and performance which make my work easy when I perform it on my clients computers. So unless there is a real need you can use little old macOS.
Pir@ted Apps: By any chance you are using pir@ted apps don’t expect that app to be working after an update to Catalina, performance-wise I personally feel Catalina is far better then macOS Mojave 10.14 faster booting speed quite responsive while opening an app.
Old Hardware: If your mac hardware is old dated like 2012, 2014 I will suggest choosing high sierra 10.13 max, as the latest macOS consume huge amount of hardware resources in terms of graphic and ram which has a huge impact on the performance while using it a very bad idea to upgrade to macOS on a MacBook Pro A1278 or A1398.