Answer from Megan, SPHR, JD:
Requiring departing employees to give notice could jeopardize their at-will status (if applicable). To avoid this, I recommend requesting that employees provide notice instead of requiring it. Asking for notice as a professional courtesy makes it more likely that you will have time to make plans to find a replacement or otherwise cover their duties. Two weeks’ notice is most common.
Beyond requesting notice, you can remind employees that their notice (or lack thereof) will be taken into consideration if they seek re-employment with the company or if a future employer asks for an employment reference. If a future employer contacts you for a reference check, you may share that the employee quit with no or insufficient notice if that is true.
Megan graduated from the University of Maryland, magna cum laude, and from Lewis and Clark Law School, cum laude. She has extensive work experience in a variety of industries, which she draws on to help clients with their HR questions.