If your customers are happy with the job you do, and you are not getting recalls.
You are happy with what you do, and the Chemicals you use. Then sod anyone elses
method, you have found the method to suit YOU!
We all do different things in different ways, as long as the end result is the same,
IE a happy customer and money in the bank, then nothing else matters.
Along the way i've done things that should never be done, but using common sense
and care can be done.
12 Months from a Diaphragm pump is about the norm, unless you don't do much work that is.