We just left it open.

They are definitely pricier than HD, but Room and Board lets you choose whether you want the overhang or not.

I get Ikea with no top and order it like I want.. I do not think it is a big deal though to have that tiny space other than once in a while you will need to dust there.

Home Depot sells a variety of filler strips and panels that you can use to close the gap.

It’s common, but if you don’t like the overhang, HD carries flush side styles.

There could still be a gap, but it will look neater.

Versus

Here’s a good option as the surrounding empty space creates an airy, balanced feel.

What size gap are you talking about?

Some vanities have a 1/2 inch overlay on each side. I would use a filler strip to close the gap.

Some have a narrow gap (less than 1/4") I would use caulk to close the gap.