If it ain't broke, don't fix it' is the slogan of the complacent, the arrogant or the scared. It's an excuse for inaction, a call to non-arms.

If it ain't broke don't fix it

We've always done it this way" is invalid when that way hasn't led to more life, greater growth, or maximum efficiency. Take that how you will...business, personally, church, or family. Complacency is too easy to breed, and already has one foot in the grave.

Complacency delivered us into the hands of evil greedy men like Cheney.

Contentment - being happy while doing something - and complacency - being happy while doing nothing - are entirely different.

You know the old adage. If it ain't broke, don't fix it.