do I have to purchase again, only bought QB in July 2017, now I have to upgrade again?
Thanks for using QuickBooks Desktop, dbirse01.
Standalone QuickBooks Desktop has a three-year supported life span. This means that if you're using QuickBooks 2017, you'll be asked to upgrade after three years (2020).
Just a brief background though, after June 1, 2018, access to add-on services will be discontinued for QuickBooks Desktop 2015 only.
Feel free to visit this article for more details: Service discontinuation policy and upgrade information.
Let me know if you need any assistance with QuickBooks. I'm always here to help.