We only had an option to add an 18" to our kitchen. We’re a family of 4 and it works well enough for us. We run it most days and twice on particularly heavy days. For us it was absolutely worth it and prevents constant arguments about having to hand wash dishes. 18"s are definitely less common than 24", but it’s not like it’s an obsolete or custom size, your going to be able to find them if needed.

What is the advantage of having a dedicated phone vs using your everyday phone?

I didn’t realize Blackberry was still in business .