Will liquid prolong the life of the machine?
Is there any advantage to either?

Jim Kent wrote

I've never seen any well-documented research
on the subject. The machine manufacturers
probably have some idea, but I wouldn't expect
them to release that publicly for fear of offending
the detergent manufacturers.

Anecdotally: I used to use Cascade powder and
had what I thought was more abrasion of glassware
(hazing) than one should expect.

If the hazing/filming can be washed off, it is likely hard water film in
which case adjusting the amount of detergent being used and using a rinse
aid may be necessary.

If the hazing doesn't wash off, it is likely 'etching' which can be caused
by prerinsing dishes so the detergent doesn't have enough food soils to act
upon, using the incorrect amount of detergent for the degree of water
hardness and wash water being too high. Most dishwasher and detergent
manufacturers recommend a wash water temperature between 120° and 140°F.

JFYI

Dan O.
-
Appliance411.com
http://ng.Appliance411.com/?ref411=dishwasher+detergent

=Ð~~~~~~