why sell maintenance the customer won't notice?

[Terry]

What maintenance on a piano will prevent future wear? Most maintenance is to
increase performance, not prevent wear.

I can think of one thing - like maybe a wobbling pedal - it works ok now,
but wear will likely occur at an increasing rate if you don't fix it.

There is also action parts alignment - like a poorly aligned knuckle on a
rep lever - it will cause problems 20 years from now if you later align it
and then, after regulation, it goes out of regulation quickly because the
knuckle was resting on a little ridge of leather from the old alignment. I
don't know that you should really call that preventing wear though. If they
never align it properly, it would last as long.

I'm not trying to present an argument here, but rather further explore this
whole question. I just have a hard time thinking how to use the "prevent
future wear" argument.

Terry Farrell

SNIP

If the needed work will prevent future wear I'll liken it to changing the
oil on your car.  You won't notice much, but the car will.

David M. Porritt, RPT