As mentioned in the Personnel and Roles article, UAS programs should give strong consideration to having staff that are dedicated to hardware and software maintenance. These personnel would be responsible for keeping up with the physical hardware status, firmware updates, and proper management of accessories and equipment.
For each piece of equipment, review the product documentation and follow any maintenance guidelines that are included. With any device, pay special attention to connectors, charge ports, buttons, or any other physical touchpoints on the device. Batteries, props, cables, antennas, even cases - anything flexible, fragile, or with protruding parts will need to be checked on a regular basis. Consider the environment you frequently fly in when you build out your checklists to account for anything you might encounter, such as heat, humidity, dust, and so on.
Set up a regular schedule for all equipment. Different organizations have different requirements for frequency of maintenance, but in general follow any professional guidelines or manufacturer's recommendations. Any supporting accessories - tablets, controllers, hotspots or other network equipment, and so on - should be on a similar cadence, if only to minimize confusion and keep any equipment from falling through the cracks.