The oil may look crystal clear on the dipstick at 3,000 miles, but most likely it will look dirty when you drain it. You are looking through only .020" of oil on the dipstick, so it will look much clearer than it will while draining out or in the drain pan.
You may have a great tech, but don't listen to him discourage frequent oil changes. He certainly doesn't abide by the old saying that "the customer is always right". Ask him how long his car lasts since he doesn't change his oil very often.
Additionally, oil can look very clean, but there are other things that may require the oil to be drained. For instance, there are additives in the oil to deal with moisture that may condense into the oil, especially in the winter. These additives will eventually deplete themselves, especially in a car that is driven short hops(less than about 15 miles).
The oil in all my gas cars gets to a very light brown before my 3,000 mile oil changes. The one exception is my C240 in which I run Mobil One and change it between the dealer changes, which means about 5,000 miles. This oil is pretty clear when it comes out.
Have a great day,