12 years an owner (nearly) - General Maintenance
Apart from the regular maintenance which is now by Hartech I have done some work myself over the years as follows:
Generally replaced the black torx fasteners in the wheel arches and across the top of the rear PU (in the engine bay) as they were showing signs of corrosion.
I recently removed the diagonal body tie/cross bars on the underside that run from in front of the rear wheels towards the engine (see pic). These were quite corroded, especially where they run in front of the rear wheels and at the bolts. I prepped them on the bench using a drill attachment and then undercoated and top coated twice with good quality metal paint. The pic isn't my car, just one I found that shows the part.
Last year Hartech advised me that the front suspension units were corroded (below the springs). So this year I put the car on axle stands and spent a couple of days rubbing them down (tricky on the car but with a dremmel and the wheels off not too bad). Then a couple of under coats and top coats with plenty of drying time in between.
I am on my third windscreen, I feel sure that the replacements don't wear as well as the original did, showing minor chips more easily - or maybe its just me?
Last year I removed all the wheel arch liners and cleaned behind checking for any corrosion - it's surprising how much dirt collects behind these - see pic.
Others that I recall: air/oil separator had to be replaced; recently developed a terrible and worrying noise when running so was low loaded to Hartech, turned out to be the inside of one catalytic convertor had failed and was rattling around
; both the condensers replaced, various ignition coils, battery . . . .
The rest is pretty standard cleaning and polishing (standard for the sort of people on here, mental according to my family) - although to be fair to my family I do have a home made water purifier just for the car as out of the tap its full of limestone around here and that doesn't go well with a black car!