I would not say to never buy a vehicle with that mileage. Mileage only tells you one thing: how far a car has traveled. It tells you NOTHING in terms of life left. Maintenance is the key to that. And those older V8 Fords had long lives.

Get a mechanic to check it out. If all is good, go for it. You're not looking at much money I'm sure. Just don't overpay.

Never buy a used vehicle with that many miles...have you asked the seller if timing chain or belt was replaced?

Which V8?  I thought a 2010 Explorer was V6

2010 Ford Explorer V8: 4.6L SOHC engine, basically the same engine as used in the Panther vehicles (Crown Vic, Grand Marquis, Town Car) but mated to a 6-speed auto trans.

IF the engine and drivetrain as a whole was properly maintained, they can be very reliable and have extended longevity.

That being said, 155K miles is at the edge of a vehicle I would recommend for purchase. The miles may have been urban (bad), suburban (so-so) or highway (better/good) and could sway a purchase decision either way.

To begin, I'd suggest getting a good inspection w/written findings, then try to look into vehicle history and service records.

Any notable hick-ups and I'd walk away.