LOL growing up I saw many a small tractor used like a Walmart motorized fat people cart... seat cracked and tires worn out but like new everywhere else400 hrs in 23 months?
that's only 4 hours per week.
It all comes down to how many chores/jobs you find for your tractor.
OP must have lots uses for his tractor. More than most including me.
Mowing several acres of lawn all summer long, plowing/blowing snow on a 1/2 mile long driveway, doing garden/farming work, making 10 cords of firewood and running up and down the driveway to get the mail and you too can get 400 hours on a tractor in 2 years time.
Its not like they are a needed tool for a every day job. If they were they'd have over 1000 hours in 2 years easy.
I would not have issues buying a 2 year old machine with 400 hours on it.
With that low of hours its more about how it was maintained and used than how many hours are on it.
One of my first jobs in the Machining business was at a small 5 man Tool Shop.LOL growing up I saw many a small tractor used like a Walmart motorized fat people cart... seat cracked and tires worn out but like new everywhere else