FUNCTION NEEDED: Update formula field daily

FUNCTION NEEDED: Update formula field daily

Hey there!

I have a situation with a client where they're calculating the number of days between a custom date field and today's date in a formula field on a contact record.

The problem is that field doesn't update unless something else on the record is updated. It doesn't update daily.

Is there a function we can write that would update that formula field daily?

Thank you!