Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

How far do I go with a mortgage approval process when shopping around?
As per my comments, I think this is up to you and how much work you want to put forth.  I do not feel it is trivial to provide documentation even with 90% of it will be the same among lenders. See this question: First answer, third and fourth paragraphs. You need to go as far as understanding the total cost of the loan, you probably need a good faith estimate.  I would also compare a minimum of three lenders.