Depending on the product, you would only use them once every month or two like a booster. Not on a week basis after every wash. Build up might not be a big deal, but it is a waste of product and money.
The word "detailer" in this context is starting to get misused, IMO.
I consider a "detailer" product a "quick detailer". Those are products which have some cleaning properties as well as a tiny bit of "something" that will add a bit of gloss to the surface. The type of product you'd use to wipe off random smudges, bird droppings, or even do a wipe down of a dusty garage queen. ECH2O mixed at 1:20 would fall into this catagory.
Many of the "detailers" claiming months of durability are really nothing more than a booster, topper, or even a spray sealant IMO. They have a place in the market for those who want to use them, but I think they need to be marketed better. I learned this lesson with CarPro's Elixr. I was expecting a product with light cleaning ability and limited (i.e. a week or two) durability. What I found was it had little/no cleaning ability and durability of about 6 weeks-ish. For this reason (and others) I've stuck to ECH2O because it is far more versatile for my uses.