What tile size is ideal for the bathroom?

60x60 is a great size. I would choose it again and again.

Do I understand this correctly? Floor and walls different dimensions? I would go for a uniform dimension because of the joint pattern.

I would go for a consistent joint pattern based on the joint image

Everything can be coordinated. Floor 60x60, wall 120x45, wall only shower area and behind the toilet. Mosaic behind the washbasin. Joint pattern is great. Don’t save on the hourly wage, then it will work. Rule: It has to please. Good joints also don’t rot.

Everything can be coordinated. Floor 60x60, wall 120x45, wall only shower area and behind the toilet. Mosaic behind the washbasin. The grout pattern is great. Don’t save on the hourly wage, then it works. Rule: It has to please. Good grout doesn’t rot either.

That’s certainly correct. We were shown different grout patterns. If the wall and floor grout don’t align, it looked strange to us. As you already say, it has to please.

That is certainly correct. We were shown different joint patterns. If the wall and floor joint don’t align, it looked strange to us.
As you already say, it has to please.

It looks odd when the joints of the wall and floor are just slightly off. With different formats, it’s best to deliberately space the joints further apart.
Otherwise, I think you get used to everything. It also depends a bit on the floor plan which tile formats fit well.

In reality, there are always things standing there. Towel racks, trash bins, shelves, cabinets, bathrobes hanging on hooks, etc. Who still notices joint misalignment there?