What are the symptoms that make them think the pump is failing? Usually they either work or don't. BTW looking at the picture you posted those kind of tanks can get water logged making the pump cycle frequently and a loss of pressure. The water BTW should be safe to drink.
The way she described how it was working, it doesn't sound waterlogged. But you are right, the non-bladder tanks are susceptible to waterlogging.
Here's my thread from yesterday describing the symptoms:
http://www.freerepublic.com/focus/f-chat/1716689/posts
Post 54 & 57 are about what the well guy had to say and how it's working now.
Thanks again to everyone for the help. You're all wunnerful!