Never buy a product with a serial number of “1”.
Following that advice, I tend to stay a couple of iterations behind in everything, while the bugs are worked out.
Don’t start changing in things in mid-project is excellent advice.
I’d recommend clearing your cache, resetting your preferences and making sure you have plenty of extra space on your hard drive. Plan on leaving 15-20% of your drive vacant. I also sometimes do a Safe Mode Start of my Mac, then restart. The shutdown in Safe Mode is supposed to initiate some repairs. And speaking of repairs, might not hurt to run drive repair but be sure you save the entire project off to another drive before you do that. And if you can do it – run as clean as possible keeping only the applications you absolutely need. I run Premiere Pro and Photoshop together a lot. Whenever I open Illustrator – I’m almost guaranteed a crash. Adobe has never gotten that partnership correct – and I have no idea whether it’s Illustrator of the OS or my hardware, as I’ve changed versions of the OS and Illustrator several times. You might also want to keep a log (use pencil and paper) of what you were doing the moment you had a problem.
Others in this forum should have more advice. Good luck!