RE refrigerator: clean the coils and get the dust bunnies out from behind and below. Leave a little bigger gap behind for better airflow.
I keep my vehicle washed, waxed and detailed. I do my own oil changes and run full synthetic Mobil 1. I also wash the frame each fall and spray it with fluid film. Cars are the most expensive thing we own for depreciation and maintenance. I keep them as long as I can. In Ohio the salt kills them before the miles. I change transmission fluids, differentials, power steering, brakes, and anything else I can do myself. Fluids are cheap compared to transmissions, and engines.
I flush my hot water heaters every 6 months. I also use a water softener. It literally doubles or triples the life of faucets, water heaters, washers, and you use way less soap.
I try to keep all of my tools and equipment maintained, wiped down and organized. It all adds up in the end!
One of my best side gigs is buying power equipment and refurbishing it. People don't take care of anything. I flush out the fuel, clean up the carbs, and clean everything up. A non running snowblower is worth $75... A spit shined and tuned one during a snow storm is worth $500. Outboard motors, generators, chainsaws, power washers.... I have figured almost all of them out thanks to the youtube. It has made a lot of free cash and I mow grass, trim trees, and blow snow with them in the mean time for money. I mow three of my neighbor's yards and all of my own. It really adds up quick. All of it is thanks to no one maintaining their stuff and being to "busy" to mow.