This typically depends on how often you use your RV. If you’re a full-time RV enthusiast, you’re going to want to have certain systems, including your air conditioning and furnace looked at and cleaned at least once a year. You should also have your brakes checked and bearings repacked once a year, or every 10,000 miles – whichever comes first. If you’re living in your RV at a park full-time, just make sure you get your brakes and bearings checked and serviced before you set out on the road again. Bearing grease will break down over time, and brake parts will rust-up, so it’s best to be proactive. There are other items to check routinely, including your RV’s roof and exterior wall sealants, overall roof condition, jack systems, and any other systems that you frequently use. These need to be checked or operated and lubricated every six months or so in order to ensure that they’re functional and keeping the elements out – water is an RV’s WORST enemy!