Spoke breakage and tire failures with so little miles on 'em we would not consider 'fair wear and tare'. . . but then again you did not sink a ton of money in this tandem and you cannot expect top quality/durability at this price.
Kenda tires have not been our favorites as they did not last long in the 700x23 version. An inexpensive tire that has some wear issues.
The bike shop seems to have served you OK; but would not sink a lots of $$ in this bike as you will not recapture that when you decide to sell it. It does give you, however, an introduction into tandeming and your next 2-seater will reflect that.
Good luck and enjoy riding TWOgether!
Rudy and Kay/Zona tandem
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