I don't think start/stop belongs in your list of useless knick-knacks that are prone to failure -- the Prius has been in production for about 18 years, and it's used start/stop from the beginning to save fuel. But you don't hear of large numbers of Priuses stuck at red lights when their engine computer forgot how to start the engine.
Start-stop can save significant fuel - 3% - 12% by some estimates, and it comes at very little cost and complexity.
True. stop-start might have not been the best example in this case. But still, i would be quite apprehensive of buying a 10-year old european car that has stop-start built in - Much more than an equivalent toyota. Japanese are quite slow to follow in implementing new features and as a result (IMO) their implementations seem to be more reliable. I have experienced European cars to develop serious electrical issues over the years. Couple that with a stop-start system, and you are looking at an undrivable car.
edit: In the past couple of years things seemed to have mixed up a bit in the industry (for example American cars have quite improved in quality). So who knows, maybe today's cars might hold up much better 10 years into their life , than their predecessors. But increasing incorporation of software and electronics into these probably will not help them get there.
The continuous start-stop wears out the engine faster, so it won't last as long as an identical model with the same engine that hasn't that feature.
It's like switching a traditional light bulb on and off in a continuous way - it won't last years (some 100+ old light bulbs still work fine, but the were powered-off just a handful times).
Do you have a reference for that? Cold engine starts cause a lot of wear, but warm engine starts should cause very little wear, especially in an engine designed for start stop.
While a home light bulb may not stand up to continuous on/off cycles, a bulb that's designed to do so (like a low-voltage bulb with a heavy filament) can last for a very long time.
So I wouldn't retrofit an existing car with a start-stop system, but I wouldn't have any qualms about purchasing a car with a start-stop engine as it would have been designed for the purpose.
>The continuous start-stop wears out the engine faster, so it won't last as long as an identical model with the same engine that hasn't that feature.
Yes, that too. Although I imagine it would wear out certain components of the engine (such as starter-motor, and crankshaft?) and battery rather than the engine as a whole.
Total-Cost-of-Ownership-wise, a stop-start might save more in fuel than it would cost in increased repairs (Or it may not, depending on make and model among other things).
Start-stop can save significant fuel - 3% - 12% by some estimates, and it comes at very little cost and complexity.