Mine are 10 1/4". I measured our plates and based it on that. (We use small plates...you know, portion control, or so we hope.) These have been working well for us so far (just a few weeks.) I have an area for plates/bowls, one for glasses (these are on either side of a window) and then more shelves in the baking area. Sorry pics are so huge. This first picture really makes me realize how much kitchen real estate I've devoted to tea. by the sink:

I cook multiple times a day and have open shelving. I clean them like I clean the rest of my kitchen. I had concerns as you do now but the dirtiest parts of my kitchen on a daily basis are the sinks and the garbage pullout. Oh, and the refrigerator handles. And under the stools where my kids sit. And the corner between the cabinets and wall where my dog lays and drools and his fur rubs everywhere. The shelves fall somewhere on the list, too, but not at the top.

Congrats. You have done a beautiful job so far. We consult on about 30 to 50 kitchens a year. Nice to see one as fun as this. Couple of points. Love the backsplash behind the stove. But any grease pops will hit the wall on either side. What if you do the white subway on either side of the backsplash you have and also on the sink side. It could be beautiful and functional. And since the tiles you have now are aligned, we would do the subway in a running pattern. (staggered) Love the visual idea of open shelving, if its fits your style and needs. And would love to see a little wood brought on to add a touch of warmth. Just look at the bit of warm color in the door mat, and imagine some of that warmth on the walls. And as far as the subway tile, it is totally fine to mix in a bit of traditional with the more contemporary pieces. This keeps the space eclectic and fresh, as well as more unique. Great job so far.

When these shelves were common, kitchens lacked dishwashers, and -- as a result... as a result they became damaged from the hot water activity going on in the sink! My aunt has them in her 1950s house. There was no dishwasher until sometime in the 1980s. The finish on the shelves didn't hold up, but the wood itself is just fine. She keeps little plants and the occasional small objet from her grandkids on them. I have half-round shelves at the end of the peninsula under the countertop, and smaller ones at the end of the overhead peninsula cabinets, in my 1960 house. The smaller shelves just hold seasonal objets. The lower ones hold the napkins, salad spinner (because we use it often and there's no place else for it), Joy of Cooking, and some cute vintage-wannabe bowls. Those just get the dust washed out quickly when we use them.