Do you see what we see?
Quality detailers come few and far between. It takes quite a bit more than just a sponge and a hose. The difference between the job you do for yourself and the job a professional detailer will do for you is pretty drastic.
I took the day off this past weekend and was watching my neighbors detail their cars. In just making conversation, I joked about how I "knew a guy" who could definitely lend a hand. The comment received a chuckle. I let the whole conversation pass and continued watching their techniques. Mentally I was keeping track of where our techniques differed. I never once criticized their trials. I only offered suggestion and guidance when they were dismayed by their own work. The comment that threw me the most off course was regarding cost. While yes, professionally detailing a vehicle can add up cost-wise, the overall benefits outweigh the negatives.
Doing the research on how to achieve the results you're after is a good start. Knowing and having a good rapport with your detailer will help guide them to your expected results. They will have advice after getting to know your vehicle and will catch virtually any quirks that the car tries to hide. True professional detailers have the trained eye to catch even the slightest inconsistencies from paint applications to weave within the carpet. This is why they charge the money that they do. As masters in their trade, they are trying to keep your car held in the highest condition it can offer. Their overall job is to show you how a little investment at the start will build itself in years added to the life and value of your car.