my mom bought a pontiac sunbird from her mom , who only ran it a few minuets per day at 25 mph --momma got stuck in an intersection and hit by another car because the dang thing was so abused----mom was ok but car didnt survive......need to run engines well and over long periods of time, not just short hops to ihop or store or in slip for 15 mins--need to run it for a few hours into a brisk storm or some such to exercise it---i love watching the yacht clubbies run theirs for a few mins a day and wonder why it doesnt work after short time of a few yrs---they never go anywhere----granted a storm setting is a bit extreme, but is a good example.....dont need to get that severe--just run under load for more than a few minuets every week.....Any engine gas or diesel will suffer from short run use. The fifteen year old sedan with 10,000 miles on ,owned by a little old lady who only drove it to her church and for groceries once a week may not be a great bargain.