Depends on the configuration.

I just purchased a 24 in vanity with just doors, but it has an adjustable shelf inside. I would have also done drawers, but to my eye at that size they looked like they wouldn't hold much. Either very shallow or very narrow, and for a powder room I did not have much that would work in there.

My full bath is 48 inches and has a door and 2 drawers on each side. Love the drawers! They are not very wide, but it does fit an 8 pack of Irish Spring nicely and they are tall enough for all my bottles.

I'd think about what needs to go in there, and keep that in mind when evaluating any given option.

We just yanked out a two-door vanity in our guest bath and will be installing a three-drawer vanity in a few weeks. It has two shallow and one deep drawer, about 11" wide. Even if the drawers are small, it gets the toothpaste, comb, and brush off the counter. They can hold make-up, a bottle of Tylenol, a bar of soap. The deep drawer will hold a blow dryer. Also, they are full-extension, so there's easy access to the entire drawer.

Our old vanity was 36", and cleaning products and TP took up half of the space. I also didn't like having to reach to the floor for everything.

We had all three of our vanities made by a local guy. Trials and tribulations aside (he had some personal issues at the time and disappeared for awhile, twice--in the middle of the builds!), we are glad we went that route. We modeled our vanities after the Sonia Europa (31.5" width and 24" width), with modifications that made the vanities work even better for us (taller overall, which made the drawers taller--win-win!). Drawers are full extension, with Blum soft close/self-close drawer glides.

I find the storage space to be terrific in both the open space(s) behind the sliding doors, as well as in the drawers (in the guest bathroom I store bath and hand towels for that bathroom in the drawers).