Depends on the size and style of the bathroom.

Floor-to-ceiling in the shower or tub surround is common, as is tiling the ceiling in those same areas.

Countertop-to-ceiling is somewhat common behind the vanity.

For the other walls in the bathroom, it's an "it depends" thing; size of the room, features in the room, cabinetry, lighting, style, etc.

A half-wall of tile (wainscot) is more common than full walls of tile on regular bathroom walls.

There might be a single wall of tile somewhere, a feature wall. The other walls may be just drywall/plaster of just a tile wainscot so color can be added to the room with paint on the upper part of the wall.

Being a hard/durable surface, if there is a lot of tile in the room, the tile color will generally set the color scheme if the tile has a color. If the tile is neutral colored, it can compliment whatever accent colors you add later, and those accent colors can be changed over the seasons or over the years for a change of pace.

Same with texture. A natural stone tile can dominate a room with color and texture. That might be fine with marble, which is timeless. But if you chose a "current trend", you might find yourself reaching for a demo hammer after a couple of years when the design community realizes sales have flattened out and they come up on the next trend to cram down your throat.

If you're unsure about your own style, clipping photos or collecting houzz pics, you'll eventually notice a trend in your collection. That's YOUR style. You can often meld your style with the latest trend, etc, essentially honoring your style and being trend relevant if that's important to you, or if resale may be a consideration.

Thank you so much. I think I will end up doing half everywhere except by the shower. It almost seems overwhelming when the whole room is tiled up to the ceiling.

You're welcome.

I just tiled an entire bathroom floor to ceiling on all the walls. And also above the shower on the ceiling. It is a smaller bathroom, and I was concerned how it would look. But it turned out great. It is definitely something more of a contemporary style which is what I was looking for. I would only do this with large sized tiles. Mine were 12"X24". I would also highly recommend tile on the ceiling over the shower to help with moisture protection. I do not like painted ceilings in those areas.