[quote user="@cakana"]

Jackie - my husband is the same way about any work done on the house. He's so neurotic that he ends up doing 1/2 the work. We just had new fencing put up along the front of the house and he was out there all day *helping*. I do think the extra oversight ensures the job is done right but I feel for the contractors.

As a service tech, all I can say is "NO, don't do it".  The "help" usually means the job takes longer, the distraction can mean somethings are missed.  I've had customers pick up factory direction sheets I was using and walk off with them, move tools, and offer advise that would burn their house down or kill someone.  My little prayer is "God save me from customers with tools".   You hire trained and experience people to do a job.  Let them.  Check the results when the job is done.  I actually told one customer  that I couldn't do what he wanted the way he wanted, packed up my tools and left.  Contrary to popular belief, the customer is rarely right.  It just doesn't pay to point this out to the customer.