I always beleived it's better to let the car idle ( higher ) when you run to the store on short term than to turn it off and back on again. I do lot's of higher idling in winter time.

I work for steel factory here in edmonton canada as a carrier operator ( big caterpillar ) ladle carrier it has 6 inline engine and that thing never shuts down except for oil service. I run it 10h/d 4 days a week on my shift never had a problem with the engine since they bought the thing 20 years-ago

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1979 Mercedes 300D 265 000 miles
1969 Mercedes 230.6 164 000 km