2005 GX470 with 173,000; alternator failure at maybe 80,000 (no small job with KDSS), air bags at 150,000/14 years old, A/C refrigerant service once (tightened HP line fitting, never an issue since). Changed a couple of o2 sensors after receiving failure codes/unable to smog. Both cats indicated failure at different times; local indy shop performed a chemical wash that restored operation. As you may know, these cats are attached to the exhaust manifolds. Replacement options are OEM ($2000+ a piece if I recall), or a talented welder and a generic cat, plus a bunch of R&R labor. For a while, there was one aftermarket cat/manifold assembly available for just under $1000. I bought one and returned it after the wash was a success. I mention this detail in case anybody else experiences cat failure on any vehicle; try a wash! It was about $150 with zero guarantee, just a Hail Mary that worked. Both have been holding for over five years.
Otherwise, just scheduled maintenance, tires and brakes. "Permanent" ATF changed. Bought new spark plugs with thought of changing them around 100,000; pulled one and it looked like new. Still running original plugs for now. Original shocks seem far better than they should (no indication of leak or failure), but thinking about suspension mods that would eliminate electronic ride control and air bags.