Q: Our master bathroom is quite small. The sink is in an alcove — with a linen closet on one side and a wall on the other — about 48 inches wide. Online, I've found bathroom vanities with two sinks that are 48 inches wide, but is it better to have two sinks or more counter space?
A: Except for a big, dramatic tub or shower, nothing says "spa-like luxury" more than having an expansive bathroom vanity with lots of counter space, and room for everyone to move around easily. Two sinks in a bathroom is supposed to mean two people can brush their teeth or get ready at the same time. But if there isn't even room to stand next to each other, what's the point? You might end up feeling more cramped.
With a small bathroom, you'll need to make some hard choices concerning the space you have. As you probably realize, a vanity only 48 inches wide doesn't give you much counter space with one sink, let alone two. And sacrificing valuable storage from your linen closet isn't worth it unless you have other options in the bathroom or in the hall nearby. Storage under the sink(s) is better than none, but not nearly as versatile as a linen closet.
To have truly functional elbow space at a bathroom vanity, you'll feel more comfortable with closer to 30 inches, or better yet, 36 inches of space, per person. Otherwise, it's likely you will still take turns brushing your teeth, even with two sinks. Sometimes you can "borrow" space if you can move around a freestanding vanity, but it sounds like that isn't a possibility in your bathroom.
Some ways to make a small bathroom vanity feel larger include having the sink off to one side, which will give you more counter space, and adding the widest mirror you can fit. Squeezing in to see your reflection makes a bathroom feel small. A medicine cabinet adds useful storage for many items you'd usually want on the counter. An open shelf below the mirror also adds storage space for small things and something decorative while leaving your counter clutter-free.