There is another recent thread re: niches wherein my DH wrote in detail about building our niches. He built ours, taking into acct our storage needs of bottles and soaps, and the shape/size of our tile. However, once our tile guys started installing our tile, DH did have to make some adjustments to the niches themselves to allow for full tiles as needed, etc.

Thanks for all the replies! I measure our shampoo bottles, the tallest is currently 12 inches, but we do sometimes buy form Costco, so maybe allowing that 16 inch someone mentioned is best. Bill, what are the dimensions on your middle one? It looks fairly tall/narrow, as do igloochic's. I think we'll end up that way, as we'll probably be limited to the 13 inches wide between studs. I think I like the 22-inch tall idea, with 18 in for bottles, an inch for the shelf itself, and then 3 inches for soap, razors, other short items. Anyone see issues with 13 by 22 inch size? It may look a little tall and narrow, and hopefully the 3 inch height is tall enough for short stuff? And good thought to stay on top of them doing it! The designer our contractor has on staff will draw it up for us, including shelf, so hopefully it's then their fault if they install it wrong (and even more hopefully, they'll do it right the first time!)

There initially was a comment before mine dated May 26, 2017 which was deleted. It does look silly without it still being there. Many pros look at the date prior to opening a thread. There is a current thread in the pro to pro section on this very topic due to some recent Houzz format changes. By using an old thread you are short changing yourself on available advise. Also due to the rapid advances in technology and products available now many responses given 5 years ago will not be the same as the ones provided to you today. Not to say there is not valuable information in older threads. That's why I bring it up and why you should care. There is your 2017 answer:)

I think this is what you are saying. Your niches are not like the original image but they are lined up in the middle of a row of tiles. But within that row, one niche is 3/8" higher than the other, like this: It would bug the heck out of me that they didn't start on a full tile in the first place, but that's usually how it ends up most of the time, like A or B. On top of that there is the3/8" height difference. I would have to compensate for this at the very least but using grout that matched the tile so I wasn't visually measuring that all the time. However, I was trained to differentiate between 0.5 of a mm for my job at one point, so 3/8" is huge to me visually. Not so with many people. Why do you know about it? Did you notice it yourself? If you did I think you have to have him change it. But if not, use grout that minimizes it.