Should be obvious, but just in case: if you get an automated call that your Windows license key has expired, don’t return the call. It’s a scam. Windows keys don’t expire and Microsoft won’t call you about something like this.
Between the Sheets — Excel podcast episode 31: Excel’s secret DATEDIF function
A quick and simple way of finding the number of days, months or years between two dates is Excel’s secret DATEDIF function. When you type it in a worksheet, there’s no popup syntax help to indicate the function exists.