“For maximum product satisfaction, please discard before using”.

The term “durability” generally refers to the length of time a product will perform the task which you purchased it for, as compared to the length of time a similar or competitive product would perform the same task.

A designer can usually make a product more durable by making it thicker, by using stronger materials than the competitor, adding internal structural bracing and gusseting in injection molded parts or by using individual components which are designed to last longer.  The tradeoff is COST, either in mold or tooling design, materials, labor, or all three.

When evaluating the durability of a product, it is most important to make a judgment as to whether the prospective customer will want to pay an additional cost in order to have the product last longer.

A good example might be a plastic fork for use at picnics.  Many times I have picked up one of these products and immediately “blew it up” trying to cut a steak or a potato. Granted, it makes me angry, but I simply get another one and hardly miss a stroke.  If you asked me would I LIKE to have a stronger plastic fork, I would certainly say YES.

However, if you asked me if I would be willing to pay more for the fork, I would respond with a definite “NO”.  The designers of the forks know this, and they design them to be barely strong enough for the average picnic attendee to barely get through a plate of average picnic entrees, of average texture and firmness, before the darn thing breaks in half.  They put no more plastic in them than is absolutely necessary, because they know that most people who are shopping for this particular item are shopping for price, not durability.

Durability will be of much more concern and price will be of much less concern on items like parachutes (trust me on this one, a parachute saved my life once), airplane parts, mountain climbing ropes, lifeboats, scuba diving tanks, machine guns, bullets, and gas masks.

The bottom line here is that the evaluator must consider:

• The length of time the product will last relative to competitive products of approximately the same price.

• The cost versus value trade-off that consumers perceive when evaluating competitive products that have different expected “useful lives” and different purchase prices.