Typical saltwater outboard can do 1000 hours before irregular maintenance destroys it.
I've seen commercial engines that made it 2500 hours due to a religious maintenance schedule.
Big problem is corrosion, metal fatigue and the design life of the electronics.
Running the engine at 3/4 throttle or less improves the chances of a longer lifespan.
I'm going to have to disagree with you a little, out of all the people boats I work and have worked on my crabber use their boats the most and do as little maintenance as possible with only 2 speeds idle and WOT, they only bring it to me when it won't run and they get the most use/hrs than anyone. I have seen one older 88hp OMC that had 4800hrs which is insane. My father in law has 480hrs on his engine which only has ever seen fresh water and is babied can't stand to ride with him I'm like go it's a bass boat with a 225hp no need to do 40mph twist the darn prop already and it's on it 2nd power head and the Maintenance is done because I do it FREE (sucks to have family with a boat).
I also will say Yamaha, Zuke, and BMC electronics are good on average to 10,000hrs they just don't go bad.
Now with that being said I will always buy a motor with lower hours than high hours condition being the same. I will also state if I'm buying a used boat and it has more than 350hrs I'm going to keep looking. I also believe that a motor ran at 3/4 or less throttle puts more strain on the engine I run my engine within 10% of the max RPM range 90% of the time. All of this is info for 2stroke engines only 4 strokes are a different breed.
