This customer had been suffering with a bunch of small problems with their computer when we arrived.
So they eventually called us up when they could no longer handle all of the little annoyances. (Sound familiar?) They said they wanted us to come out to their home office and take a look at their computer. With a little bit of trepidation, we said sure because sometimes 'little' problems are only the tip of the iceberg of a much larger problem.
So we show up, and they pull out a list of problems that they wanted us to address. We review the list and they really were small problems. The problems were nothing significant but just annoying. This was FABULOUS!
The list helped guide the conversation and gave us a checklist of what needed to be done. We went down step by step on the list and fixed, educated, or investigated each one. We were there for 2 hours but that was 2 hours of solid non-stop work. It was great for the customer but a little bit tiring for us. :) We even got high-fived for fixing the most annoying problem. That may be our first high five from a customer!
So just like the Boy & Girl Scouts, you should 'Be Prepared.' Lists gives the tech a sense of accomplishment and the customer knows that everything gets addressed so it is a WIN - WIN.