I am pain in the ass. But!, will ask you so many questions you always wanted answered, that you gently swept under the carpet. You only loose some of your time, however, you will at least get confirmation that you have all answers.
I am in that stage of my life where it is not important to me to accept as much work as possible, but to select what is meaningful.
Two main reasons: 1 - it shows that you are serious about job-to-be-done; 2 - I will use it to include and pay other professionals in the workshop.
My model works as a bridge between you and service providers, therefore I take a fee from service providers (like I am included into price). If I cannot influence both sides (service providers and you as a client) to have simple and meaningful work, communication, and transparency, you will get red alert to cut it. Therefore, we all loose.
I worked with many professionals over the years, and now many of them have their own IT companies. These are people that I worked with, been in the trenches with, and know what to expect from them. Mostly, these are small digital product development companies, that love interesting products and projects, and not looking for enterprise projects for big teams.