If you restrict the cabinet to a single door you have physical problems when it gets too big. Mine have mirrored fronts and inside fronts, so the doors are heavy, and the heavy sheets of mirror glass are only stuck on to the outside metal door frame with double sided tape, which in it's turn sticks only as well as the grey paint covering the back of the mirror's glass. It's really good tape, but one bad day, one bad bump in an overheated bathroom and you could have lots of glass to sweep up. EDIT: Been there. Done that.

The other problem with single doors is they have to swing out into personal face-space to open, and if you have a 24 inch door on a wall 21 inches away, you're already in ducking range. Any bigger and there's a real risk of your eyeball or the top of your head contacting the edge or corner of a beveled piece of glass in a permanently unwholesome manner. Beveled frameless glass doors are seriously dangerous; some corners get pretty sharply chipped after a few years of use.

I like huge fully mirrored cabinets. They're wonderful. I have one 36 inch vanity with a 36 inch double door unit above it and a 21 inch one at the side at right angles to the first, opening away from the person. I'm (today) roughing out a wall for a 48 inch triple door cabinet over a 60 inch top, and each door is only 16 inches. There will be no side units because of the same pocket door problem you have. None of the mentioned doors reach out far.

It's critical that the blind people (and the clumsy ones like me) in our house do not have any serious problems with contacting glass edges accidentally. I have kids, grandkids trying to climb onto the vanity with the cabinet door open to reach toothpaste, eighty to ninety year old inlaws, blind visitors to the house who don't know the bathroom layout, and half-asleep -me- in the room at 3:00 a.m, so I see these things as a safety issue.

To finally answer your question: visually, the bigger the better.

This post was edited by grubby_me on Mon, Jan 12, 15 at 14:33

Do you plan to put sconces on each side of the medicine cabinet? Do you care whether the sconces are mounted wider than the vanity below?

Bigger IS better...but...it's a small space.

I'm planning on putting a fixture above the mirror/cabinet--we just don't have that much space for sconces. The vanity is against the wall on one side.

I could just do a mirror and skip the medicine cabinet entirely if that would get me a better size, or recess a non-mirrored one over the toilet (right next to the vanity...)

I would do the recessed cabinet over the toilet and just get a great mirror. A guest bath doesn't have the same need for a medicine cabinet. In fact, maybe you can skip the medicine cabinet altogether if you have storage space in the vanity, especially a shallow drawer or two.

I think I might just do that...don't want guests to get too comfy anyway!

For a guest bath with drawer storage, I think skipping the medicine cabinet is just fine. We did it in our master bath actually, because we couldn't fit a recessed medicine cabinet into what is an exterior wall, and it's fine. The lighting from side sconces is nicer than from above the mirror though. . . .

We went with the Kohler - not the cheapest and not the most expensive either. We haven't installed it yet, but have taken it out of the box and checked it out. It's nicely constructed and I like that it's mirrored inside as well as out. I included the link to the one we chose, but obviously you would want one of the smaller sizes it comes in. Personally, I prefer a med cabinet to a mirror because of the extra storage and the ability to swing the mirror around to get the best angle for doing makeup. Good luck!

Here is a link that might be useful: Kohler Med Cabinet

This one is 24 x 30 above a 32" vanity. I keep everything from bandaids to disposable razors for guests inside (even a digital clock). Believe ours was made by Broan.

{{gwi:2132916}}

Looks great!

Thanks for all the suggestions!