Second hand can be more reliable than new

Ecotech Services sells a range of second hand equipment that has been repaired or refurbished.  We can offer a warranty on the equipment without fear of incurring high costs (resulting from warranty repair or for refunds) to us for a number of reasons, including our experience on failure modes and the typical faults that are expected, and because of our judgement on where it lies on the bathtub curve.

The bathtub curve is a concept in engineering that describes the reliability of a product during its lifetime.  It shows that a product is more likely to fail when it is very new or very old.

Graph of the bathtub curve

The bathtub curve is a concept that describes statistical chance of when a product fails at different points over its useful lifetime.
Image: Wikimedia Commons

In our experience the bathtub curve does appear to be applicable for a wide range of commercial, industrial, and consumer products.  However, since we don’t often have reliable data on total product sales versus number of product failures our evidence on the veracity of the bathtub curve is merely anecdotal.

If the bathtub curve is valid for a particular product and we sell it during the constant failure rate section of the curve, then we can quite rightly make the claim that they are statistically more reliable than new ones.  This is assuming that we correctly assess that the product is not in the increasing failure rate of the curve, and that the manufacturer has sold the product with a minimal burn in.  These are both reasonable assumptions.

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This is the Ecotech Services administration account. The information and opinions expressed here are those of Ecotech Services Limited.

1 Response to Second hand can be more reliable than new

  1. I learnt about the bathtub curve when I was studying for my NZCE way back in the early 1990s. I think the idea may have stuck in my brain but sometimes I may have been a bit too keen in fixing some things that were too far into the worn out part of the curve. I might have to say sorry to any of my customers who I didn’t clearly explain all of this sort of stuff.

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