I am remodeling 1 of my bathrooms in my personal residence. The 30" vanities I am looking at are $600-1,000 & MDF. These ones don't deteriorate as fast w/ water damage, right? The cheaper tier is "manufactured wood," which I am assuming isn't as quality? I figured out a long time ago not to put the cheapest (cardboard like but can't recall what they are called) vanities in bathrooms & have mostly used pedestals for a while w/ lots of wall storage in the units. Thought?

Medium density fiber (MDF) will most assuredly swell when it gets too wet.

I think that it swells easier than the pressed wood (OSB type) units. The big kicker is what the coating on the unit is.

A lot are using a thin plastic that is thermally fused to the walls. Some use a sticker.

It seems that most of the mid range and below units are so cheaply constructed that you are asking for problems.

We got a little higher quality for our house. Rentals are still whatever I can find that isn't ridiculous and still looks decent.

I started putting plastic buttons on the bottoms to keep the vanity from sitting in water from the shower or a leak. That seems to help a little. Many will paint or poly the bottom edges, but if the water gets on the wall of the unit it is usually doomed as well.

I could argue it either way.

On one hand, you likely won't abuse it like a tenant so it should last longer than in a rental. It's the cheaper option.

On the other hand, it's still particle board. If it gets wet it will swell and fall apart. Go to a cabinet shop and have them build you one out of plywood. The extra dollars spent will give you decades of service.

So it really boils down to what you want, cheap that you have to replace in the event you have a flood, or a little more expensive that will last forever.

manufactured wood is often just another name for MDF. Neither are considered good.

It is either that or plywood which is better. And often found on most RTA cabinets that Tim mentioned. A lot of RTA places online will sell them assembled for a higher price.

That said, we most often get plywood. But still have MDF last a long time. Even plywood can soak up water from the bottom where it touches the floor.

The only think you need to do is buy some 1/2"PVC. Cut strips then glue and nail on the bottom. And quarter round molding will hide this.

We use any PVC scrapes we have on hand. Or even cut strips from composite decking boards.

Then the extra step is to add anytype of vinyl flooring to the shelf in the cabinet. And caulk around this. Since can have a slow water leak that could get to the wood.

Scrap LVP or sheet flooring works well.

Also at times we will buy a RTA kitchen sink base cabinet. And very easy to cut to the proper depth. This is to give us a higher vanity height of about 34".

No, no, no! They soak up water like a sponge. Even if they're nowhere near water, the hinge screws will pull right out of the particleboard over time.

Robin, you took the words right out of my mouth! We've found those on the side of the road here. For our small bath we sanded the stain finish off our old solid cabinet, in place, nice and smooth. Then painted it with several coats of outdoor white paint, sanding in between coats. Brought a whole new look to the bathroom. New faucet and towel racks, cost nearly anything. That was 30 years ago, no wear whatsoever.

Downstairs, tenant's unit, did similar, but only painted the door to the cabinet. We bought a completely waterproof thin plastic sheet (don't know what it's called) and covered each side with it. So easily wiped and if dirty or makeup spills down the sides, doesn't need painting. In perfect shape 20 years later. I wouldn't do MDF anything anymore.