How often should we run sanction checks on staff?

Hi all – my name is Saige, and I just began working as the Compliance Officer for a small medical practice. I’m working on implementing appropriate screening protocols. Based on what I’ve read, we’re required to do sanction checks on all employees, but there’s some confusion about the frequency of the checks. Should I only check sanctions at hire or would I need to check sanctions every month? Additionally, what other databases do I need to check besides the federal ones? If there are any other compliance managers that could offer advice, that would be greatly appreciated! Thanks!