I have a townhouse that was built in 1980 and looking to replace the carpet with 20"x20" porcelain tile, I want to install it on the steps (about 15 steps), 2nd floor landing (hallway) and restrooms.

Usually when the interior won't respond to pretty basic cleaning techniques, the porcelain glaze has been worn or etched off.

We painted the cabinets, filled tons of chips, changed the doors by custom ordering them for the customer in their choice of design by a company we have an account with that has them made in Mexico for about 30% american cost, painted sink, also the appliances in professional grade metalic stainless paint, painted floor tile in a high solids porcelain urethane white after an aerospace use type primer and a high solids chemically hardened chear coat, and matched the backsplash the same way.

Amazing how fragile porcelain can be :/ To make a long story short I attempted to replace the toilet on a damaged floor without knowing about adjusting flanges or whatever the heck they are called for 2 whole days...

I have 18" light porcelain floor tile with a light colored grout.

@Ben M Cast iron or porcelain on metal tubs dont really stain...the surface can get damaged by abrasive cleaners or have heavy hard water deposits.

You just gave the main reason why both rules are, "porcelain bus" material. 

Builders here just end with tile..porcelain so beige edge (not red clay like some ceramics).

The floors are actually a nice porcelain wood tile that I ran throughout the entire house.

There are more resorts here than anywhere, golfing galore, great weather (most of the year) low taxes, a big hole in the ground called The Grand Canyon, skiing, (yes an 11,000 ft mountain for skiing) we have more peaks than Colorado I'm told, great hiking both in the desert and in the mountains, exquisite restaurants, nice people, good roads, lots of activities, and we are only hours away from the ocean.