What are they installing - another kit or tile?

Experienced contractors have credit with suppliers and don't have to pay for many things right away. 

You can figure most basic things out like painting, trim, basic carpentry, vinyl flooring, landscaping, demo, tiling on youtube.

This makes it probably the most honest earned money in RE - because you actually made things better for society by improving a property that needed it, paying contractors and suppliers and providing needed housing to the public.

This can be problematic if you have tile floors and/or walls.

Well, regarding "acting in my own interest," I was the supplier of properties.

No tool trailer, no climbing on the roof, no nail gun, nor tile saw.

Count doors, count windows, count tile space, count floor space, count roof tiles.

Same with roofing and siding suppliers.

Or do they shudder when they look at the bathroom tile?