Depends on what you expect out of it. If you're looking at a 24M on the Mercedes Sprinter Chassis, you can expect oil changes every 10K miles (per manual, I do mine more often). DEF fluid must be added every 1700-2000 miles (I just keep mine topped off after every trip). The usual other maintenance items per manufacturer's schedule.
For the coach, you'll need to monitor battery condition religiously, (else you'll find yourself dead in the water somewhere
). Roof seams need to be checked regularly to ensure you don't get leaks. If you have a generator, that too needs regularly scheduled oil changes.
You need to keep refrigerator and furnace flues and burners clean and free of spider nests - they love to dwell there.
Tire monitors are a desirable addition to keep tabs on tire pressure. A blowout on the road is no fun - changing truck tires on the side of the road in summer heat is a challenge, and summer heat can hasten a blowout if not properly inflated.
If towing, it's a good idea to make sure your equipment is safe and in good condition, including break-away cable, towbar, baseplate, and hitch assembly. Auxiliary braking is highly desired, since you're adding several thousand pounds of additonal weight on the motorhome's brakes.
Those are the major items. Like a boat, just go over it every time before you take it out, and everytime you finish a trip. You'll notice cosmetic items and minor fit/finish issues as they arise. Things like awnings, storage locker doors, etc. often need adjusting. Remember, that motorhome has most of the systems you have in your sticks and bricks home, so a lot of the same problems pop up from time to time with stoves, refrigerators, plumbing and heating, etc. It's nothing like a boat, but still - good maintenance is a necessity if you want to enjoy your motorhome.
By the way, we have the Solera M and LOVE it.