There is no real rule.

You do want them to coordinate with one another in terms of relating to the overall look of the bathroom. But they can coordinate while being different materials (porcelain on the walls versus natural stone on the floor), different sizes (subways on the wall versus squares on the floor), and different patterns (running bond on the walls versus diagonal on the floor).

The above is simply an example.

Much of it can depend on the size of the room and the amount of tile to be used. Using the same tile everywhere in a large bathroom could look a bit too monochromatic and uninteresting. There would be no change in material or pattern to draw the eye from detail to detail as you look around the room. In modern or contemporary design that might be desirable; a slick, clean, uncluttered look. In a more traditional design it might simply be boring.

Large format tile always lends itself well in modern styles. Mosaic can be implemented for a period look.

Mosaic is busy given the many individual tiles, But it can be made to look "detailed and busy" by using a contrasting grout color. It can be made to look cleaner and slicker by using a grout color the same color as the tile.

So there is no real right or wrong as a whole. Sometimes anything and everything can work, but often it's how it is implemented into the design. But you need a starting point. A design style, for example. Having an idea of what look you are trying to achieve will lead you through the selection process; tile material, tile color, tile size, layout pattern, grout color.

I agree with Mongo. The only thing I'd add is that Houzz.com is a great source of inspiration photos. If you haven't already, spend some time on Houzz where you can create a virtual Ideabook to save the photos that inspire you. It can be a little overwhelming but you'll probably see every imaginable tile combination!

I agree with both posters above. Houzz is a great place to search for elements in design or for rooms in general. For instance, I will be having a white square tile on my walls in a wainscot, set in a stacked pattern and a marble listello inserted with subtile grays and tans and whites in a smaller size and arranged in a running bond. For my floor I am going to put in a black slate in either 12x12 running bond or cut them into 6x12 and put them in a herringbone that is set square to the wall. So 3 sizes, possibly 3 layouts, 3 textures, and 3 colors. Before I decided to go this route I had a theme, I looked at pictures, I looked at samples, I laid them out in what I thought would work in real life, I drew the whole scheme up in Adobe illustrator, and now I have committed to this plan. It better work! :)

Oh, and I might add I had to really consider if my floor was up to the stone I had in mind. I found out a lot about floor deflection and what is suitable for stone. Ceramic and stone need stiff floors, but stone even more so. In my case I had to do some re-enforcing of my floor. I do not want this installation failing in the next 60 years.

enduring, what are you talking about? Of course you're going to use a herringbone on the floor. You think I went to all the trouble of posting the herringbone layout on that other thread for naught? lol

Yep, depends on what you like and are inspired by. Houzz is great. We're doing 4 baths, and have different things going on relating to the floor tiles in each. One has the same tile (well different models for floor vs shower) and they are being layed differntly. One has completly different - color on tub/wainscoat and white on floor. Third has differnt sizes wall vs. floor. (We haven't figured out fourth, but are working on keeping existing wood floor and something "different" on the walls.) See, we couldn't make up our minds and are going with what we like for the differnt baths. Good luck figuring it out!

:)I stand corrected -Yes, I am doing Herringbone Mongo!