The greatest strain on the hinge is when the bike is in use. As far as faults of assembly go, few cycle emporia actually check the whole over properly before sale. Uneven tension in the spokes will lead to failure, and a bottom bracket is locked in by the LH fitting, which, if not properly tightened, will unscrew itself. It certainly pays to learn more about checking and servicing your own bike, most of which is not too difficult. Specialist tools as required are still much less costly than failure.