We chose the floor tiles. They were beautifully laid on tile with grouted seams in the store too, it was nice to look at.
The seams there were a light beige color. (Wall tiles don't interest me here).
But we were advised not to use light colored grout, as it will darken significantly from dirt/walking/wiping in 1-2 years.
However, the tiler who ended up installing the tiles said that the darkening after 1-2 years would not be as significant or as severe as described. Also, the "rubbing" is not as severe because of the narrow 3mm joints.
Visually, of course, I would like to use lighter colored seams.
I'm hoping for actual experience from you. Do you have lighter colored joints and have you worn them for several years? How does it look to you?
My rental apartment had black tile with white grout. What material it was made of, I don't know.
I wouldn't use a lighter color grout. You could see every drop of dirt right away.
I had grout in my old house that was a silver gray color. I did the tile and grout myself, but at one point I was on my knees and brushing with an Oxi toothbrush and the like to make the grout in the room look like the edges of the room again. Failed.
I can't imagine tight joints reacting any differently.
If you consider standard cement grout for floor tile, you will naturally see soiling after a few months/some years of builder's work. It seems inevitable at first. With narrow as well as wider joints than 3 mm, it has quite a disturbing effect.
However, there are special grouting materials, in contact with which even red wine does not leave stains.
The same goes for mechanical stains, which are much easier to remove than normal stains.
We had light colored grout in a round shower made of stones and covered with glass mosaic. The seams stayed like new for a good 4 years in a house of 5, then we sold the building. Acquiring a patina on the floor is what happened to the light colored moving seams in the new house.
In our last rental apartment, the grout on the bathroom floor was a light color. It was the first move in after the renovation. In less than a year, the grout was completely different. For example, they were much darker in front of the sink. I wouldn't do that, and our tiler didn't advise it either.