I wanted to know if this uni will last a long time. 
For got to put it here it is:
http://www.amazon.com/gp/aw/d/B002LHM0Z8/ref=mp_s_a_9?qid=1327030297&sr=8-9
Quality control???
So this is a really basic unicycle. Pretty cheap too
I have used similar very cheap unicycles and the uni I learnt to ride on was similar
However as one amazon reviewer wrote:
December 15, 2010 By M. Alden
This is a poorly made, cheap Chinese unicycle that does not have a single quality part. After a few minutes of riding it for the first time, the pedal cranks started to come loose, giving a terrible bumping feeling with every rotation. The metal surrounding the cranks was chipped, making it impossible to properly tighten the crank down; it was not a matter of tightening the nut on each crank. The seat clamp was faulty on arrival. The screw was stripped, and the metal was brittle. After replacing the clamp and dealing with the bumping because of the clamps, the tire that came with the unicycle burst on its own after a few days, even though we did not overfill the tire. After replacing the tire, the spokes of the wheel started to creak, a sign of the wheel being of poor quality as well. The first unicycle we got, which has a 20-inch wheel, has not had any issues whatsoever for the ten years it has been in service, not even a leaking tire. Don’t waste your money on this disgusting item.
Yes it can be a bit of a lottery
The quality control on some of these no brand unis can be poor or non existent
Yes get a cheapish uni but maybe look at some others. A good second hand uni is also a good option
Probably not real durable, but at that price, it may be perfect as a beginner ride. Some will say to start on a 20", but either size is fine for learning unless you’re really small.