It's great to have you here and help you out with this QuickBooks licensing and system requirements concern, @rjmccann.
If you purchase the standalone version of QuickBooks Desktop, from the retail stores or with us, this can be supported for up to 3 years before it gets discontinued. For example, you got the 2020 version, it will be supported until May 31, 2023. But you can also choose not to upgrade after such time, as the license can be opened even after its discontinued. Only the add on services or updates are unsupported. To learn more about the disco policy, see this link here: QuickBooks Desktop service discontinuation policy and upgrade information
Additionally, updates are required to download critical and security patches. However, it's optional if you want to download them to ensure the program works as it should. But if you're not experiencing any problem, you can choose not to download them at your own risk.
Here's an article about the system requirements and updates: Update QuickBooks Desktop to the latest release.
Please post here again if you have other questions or concerns with your QuickBooks Desktop license. I'll be right here to help you out any time.
