A welcome feature in Microsoft Outlook 2016 (currently in public beta) is that when you want to attach a file to an e-mail message, appointment item or other screen, the Attach File icon shows the last several files you attached, so you can attach one, again:
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.