I am currently redesigning my kitchen in a 1930’s Midwestern USA house. The kitchen has a decent floor area but the floor plan is oddly restrictive.
My space next to the sink is such that I can either have a standard 24" dishwasher next to the sink and a slightly weird cabinet adjacent to it, or I could have an 18 inch dishwasher at 45 degrees flanked by two small but reasonably sized cabinet doors (or drawers), although the 45 degree plan would dictate a somewhat shallow custom counter depth on the flanks (like 18-20 inches).
I think I would be more proud of the accomplishment of building the angled design, and I think the ergonomics would be optimal.
But I’m not sure about the smaller dishwasher. I have never used a smaller one. It seems like it would be enough for my small family and still plenty helpful for gatherings.
If it was me, I’d go with a cabinet install that allows for a 24" dishwasher. That’s the standard size, and you might have trouble replacing a broken 18" dishwasher in the future.
I’ve gotten some good deals on lightly used 24" dishwashers. I’ve never seen an 18" come up, though I’m sure they’re out there. I think I paid about 50% of MSRP on my current one that has been very good to me.
I see lots of people saying there are plenty of 18"s, and I’m sure that’s true if you buy them new. I guess I just wanted to agree with you and share my experience.
18” dishwashers are still very easy to get ahold of. I’ve recently replaced one and while I had more limited options compared to 24”, there were still dozens to choose from.