Your making a new product that people will use daily. Do you make it last forever so people will be attracted to its durability or do you make it intentionally wear out so people have to buy a new one occasionally?
I go for an in between in order to keep to quality up and cost down.
Wear out if I'm in business. More sales = more business. However I'd have to make sure other competing companies were doing the same and possibly start a corporate pact.