Six,
Don't let posts like these deter you from offering this service. I know you have started doing showers and such, I was the guy who turned caulkmaster on to the steamer you bought.
I added on tile and grout restoration in 2007 and it is the driving force for extreme revenue generation in my business today. I have done thousands (no exaggeration) of color sealing jobs since 07 including floors and showers in both commercial and residential settings. In the last year, I have added on using Ecosmart, which is a silane/siloxane based non-strip topcoat that we will put on shower floors after being colored, commercial bathrooms, slate showers, and any other unique projects that would benefit from having a semi-permanent proof sealer as a barrier to color being removed. It has solved many of the problems that we would incur, especially when coloring shower floors. The product/application is a similar idea to Sani-Glaze and Adsil.
Certain floors will be a bugger, and certain expectations need to be set with them. If you have high grout lines, it was a shitty install, and will in turn still be a shitty floor after you make the grout lines look new (and you will be cussing yourself out as you wipe the color seal off because they are the same heighth as the tile). Ever heard of putting lipstick on a pig? Same scenario. These types of floors will need to be serviced on a more regular basis. Why? The customer is actually walking on the grout lines as they use the floor and in turn will dirty the grout lines faster and/or grind off the color seal. COLOR SEAL DOES NOT MAKE THE DIRT JUMP OFF THE FLOOR!!! NOTHING UNDER THE SUN IS MAINTENENCE FREE!
We are usually doing repairs on each job, wether that be regrouting areas that are necessary (sometimes we will file down high grout lines if they are going to be a problem in color sealing process), cracked tile replacement, recaulking (sooooooo much recaulking).
I carry TEC Powergrout as a replacement grout, we carry around 10 different colors on each truck, as well as TEC Accucolor 100% Silicone in matching colors, as well as those colors in color seal. This is great for showers because it allows us to make an aesthetically pleasing end product (especially in a shower) where everything matches.
Heading in the direction of tile and grout was the best decision I could have made for my business. Which will be 12 years old this July.
If you can't be on your knees, or crouching for long periods of time, don't bother with the service. Your health is more important. Im 32, and have been using Racatacs since I started and have 0 health problems (knock on wood)....tho I want more of my hair back....
EDIT: You can take a look at my website and go to the tile categories to see all sorts of color sealing projects that look amazing and like a pro did them (because one did).
www.vcleaning.com