We have rather a lot of shelves in the house, but apparently not enough. In many places we have metal rails up each side, so the shelves can be moved up and down and added to.
In a couple of places we may have too many shelves, but that is not such a serious problem any more. One problem is that each shelf alcove is a different width, so we can't simply move a shelf from where there are too many to where there are not enough, and we couldn't have ordered an extra few shelves from the carpenter, in the knowledge that we would certainly need shelves, since we were uncertain exactly where we would need them.
In one place, above the laundry shoot in the bathroom upstairs, we have extra shelves since we changed our minds about the colour. In most places we have two colours: white and dark brown. Our original order was for white shelves but we later revised it to brown since the shelves were liable to get dirty and white would show this dirt much better. In the meantime the first shelves had already been painted, so we got another three. And those three shelves have been waiting for something to happen. Specifically, waiting for us to get the small brackets that slot into the metal rails running up and down each side. The site foreman showed us where we could get them the last time he visited, which is a few months back now. It's not particularly far away, but not somewhere we usually pass, except on weekends, and then it's closed.
We made it today and the shop, Okano, is a real treasure trove of building stuff, with whole rows of drill bits, and rooms full of aluminium rods. It's the kind of place that would sell left-handed screwdrivers and bottomless buckets of sparks. They had the brackets and asked how many I wanted. I asked how many were in a box, assuming they would be cheaper that way. There were 200 in a box, and they cost 68 yen each. This seemed a lot for a little bit of metal with some rubber on it, until I got back and tried to find it on the internet, armed as I now was with a part number from the receipt. The cheapest I could find them on the internet was 84 yen, so in this case the bricks and mortar shop with the friendly people worked out cheaper. I bought fifty brackets off them, so since there are four brackets to each shelf and when I can find the other one that's left in a safe place in the house, we'll be able to put up 13 more shelves.
So next we went to the DIY shop looking at bits of wood we could use for more shelving, and were quite shocked how cheap it all was. Several pieces were available off the peg in shelf-like shapes and sizes. Actually they were often on shelves.
I'm sure with a little bit of effort all the shelves in our house could have been designed in these predetermined widths and saved the carpenter a lot of work and materials, and knocked thousands of yen off our bill.