Hmm.... I tried that and it did not work, at least for me. The water in my town is VERY full of different substances that stain tile, create a whitish film on shower doors, etc etc. I keep trying different products and techniques, and so far, nothing works really well. SO frustrating.
Also - there is the problem of TIME limits. Most of my customers cannot (and will not) pay for the extra time needed to do what you suggested. Maybe its just Florida, where the pay is low, and the cost of living is high. People have this silly idea that its cheaper to live in Florida. NOT!!! It isnt. I moved here from Boston, in 1997, and NEVER once found Florida to be a less expensive place to live. Back then, real estate WAS cheaper, but that changed in a hurry. Other things than housing were just as expensive. And now, real estate has gone WAY up.
Sometimes, I think I need 6 hands to do all the work I do! Sigh.......