How many miles can you put on a 50cc Honda Metropolitan scooter?

It is a 2008 with 6300+ miles. I have it serviced every year, and it has never had any major issues.

A Honda? At least 50,000 miles before major problems. (A Vespa will do 100,000 miles.)

With proper maintenance and stored out of the weather it could last forever.

Even when there's a wear situation, it is not hard to fix. They pull the sleeve off and replace the piston and a new sleeve and new rings and you are going again forever. There's nothing to wear out… That is costly. You can drive the wheels off of it.
I put 6600 on in one season… As I have snow winters so the bike is parked. Also do not ride in the rain. Also drive a car when I don't ride bike.

My great nephew still rides my 1965 Honda cub on his grandfathers (my brothers) farm. Its got well over 75k miles with out major repairs. The carb has been rebuilt a few times ( unleaded gas messes up carbs designed for leaded gas

Like many vehicles this size, the engine can likely go 50 or 100k miles, it will probably be a combination of other things that sideline it. When the alternator stops charging, the brakes stop braking, when the reliability becomes unreliable, and when the cost to buy new is less than the cost to maintain, it might be time to park it. With unlimited funds it can last forever.

Since it is regularly serviced any problem is unlikely to be related to the engine, most ancillaries like coils, rectifier/regulators, starters, other electric systems are easily replaced. So the frame, exhaust and wheels are left. I would guess that corrosion or unseen damage will cause its end.

40,000 miles if you maintain the scooter and charge the oil and filter every 1200 miles.
Beyond that the scooter will become uneconomical to repair.

Big wear possible problem on scooters is drive belt in CVT. 5000 miles to 10,000 miles- but belts wear and break, need regular checks and replacement. Engine with care, 20,00 miles then check rings.

DON' KNOW