How long does it take USPS to ship from New York to Seattle?

Slow Boat or Airmail?

By boat - sometimes months, By Air, sometimes days/sometimes weeks

What is it? What part of China does it come from? - Where is it going to?

If you live in Taiwan you could probably get it next day.

If it is valuable then you might consider DHL or any other large courier company with a global reputation.

The Chinese postal service is not able to track goods inward or outward. It might take months for an item to arrive at the outgoing port or airport - or it might get there in a couple of days.

None of the above is really helpful - but then again the actual answer seldom is!