Back in the South

My RX330with 257K miles is in the shop for a new radiator and passenger side steering rack. This is a single owner car. All maintenance has been done by Lexus (different ones as I moved around the country). Reasons for choosing Lexus is that work is guaranteed and all records are in the national data base. I really take good care of this vehicle and most of the miles are road miles. The car has been in 2 slow speed accidents: front accident (rain skid into stopped car in traffic) where the hood had to be replaced so it has new headlamps, bumper, etc. and a rear accident so the rear bumper was replaced. No damage was done to the frame or radiator at that those times. The tape player died as did the CD player but the radio works for the most part. I Things I've replaced include the passenger side mirror (known issue), the windshield (rocks) and the front passenger window (from a break-in). It recently received a very small dent to the rear left quarter panel while in a parking lot and I think it can be pulled out without trouble. Other than that the body looks perfect. There is no rust (although it lived in salt covered streets for the first 4 years). I've kept all records on this car from the purchase and with all maintenance done by Lexus (with the exception of body work and some oil changes done by Toyota), this vehicle has cost exactly 50 cents/mile and this includes the costs to me of insurance deductibles. insurance, gasoline and oil changes. I realize that I should start using a garage instead of a dealer to save costs. I've driven the newer models and am using a 2019 now. I love the new features, but the bulkiness and the anime design are not to my liking. I also do not want a car payment so would be looking at a used replacement. My RX330 has the original engine and original trans and I know they cannot live forever. I'm trying to understand when to give up and would appreciate thoughts.