When the Captain considers it safe and expedient to do so, it is important that crews regularly practice manually flying their aircraft. This is to maintain proficiency in basic handling and airmanship skills.
(That's the basic sentence, but if you'll accept a suggestion - also include a requirement to note it in logbooks, and a recommendation that crews practice hand-flying a certain number of hours per month - then you have something a bit firmer than a general recommendation).
G