Interesting dilema. Yes, the electronics are getting older and the 'new' replacements are not as good as the original in some cases. But you have 2 basicly good cars.

The reason you used to carry spare parts for the 240, like I do for my 122, is to make sure I won't get stranded when something known to fail does, and parts are hard to find. In you last case, the coil was probably getting weak, but the CPS failed. The mechanic replaced both, which was a good thing.

Should you start throwing parts on your car? No. It won't make it any more reliable. Your cars aren't worth much on the resale market, but they will live for a very long time. When you can no longer rely on the car to get you from A to B, then look for a newer one.

Both of your cars are 'low mileage' and relatively cheap if you DIY. At least with your 1995, you can check the OBDII codes each time you change the oil. Note and delete any codes, they will be a warning for electrical parts failure. The O2 sensors, if original, are probably getting a little slower to respond and could be replaced - but that is optional and will not kill the engine.

All I ever carried in the trunk was the folding Torx tool and some spare brake light bulbs. I think I added a few fuses once. Oh, and a paperclip in case the fuel relay died.

The time to get 'rid' of your 850s is when you get tired of them. Or when the maintenance gets greater than $1,000/year.

Klaus
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My advice is free, so you got what you paid for...