Shelf liners are available at hardware stores such as ACE Hardware. It comes in rolls, made of plastic and has ridges on one side. Use with ridges up or ridges down, your preference. I use it with ridges down so dirt will not get into the ridges which would be hard to clean. The flat surface is easy to wipe clean. I have this in all of my cabinets, dish areas and food pantry.

Plastic is better because paper will become soiled and moisture soak through onto the wood.

Another way is to use a paint sealer on the inside of cabinets and paint with gloss or semi-gloss enamel.

I lined the shelves for pots & pans with carpet runners, same with silverware drawers (easy to cut to size needed). Reduces noise and easy to vacuum.

I use shelf paper that sticks, but I don't peel the adhesive back, I just use it as loose paper.

Things inside cabinets don't get dirty. The wood of the cabinets is not going to soak up liquids as long as the liquids are in containers with lids.

I agree you don't need much but I prefer to have something under my things beside just wood.

In other houses I have had stains under the sink and I didn't like the looks of that. So I put plastic containers under my sink to hold bottles of cleaning solutions, vinegar, etc.. When I have to clean under there, I just slide out the containers. My plumber looked in there and said Wow!, good idea. LOL

I just have a thing against cabinets, I guess. Don't like 'em! I bought some non-adhesive shelf liner to put in them. PITA, but I think I'll be happier.

Rubbermaid makes something called coreguard to put under the kitchen sink--think I'll look into that.

I bought peel and stick vinyl floor tiles at Home Depot and put on all the shevling in my kitchen, utility room and bathroom cabinets. It was very easy to install, looks pretty and easy to wipe out if needed. It cuts easy with heavy duty scissors or you can score and break it.

You can paint the interiors of the cabinets with a gloss paint that is easy to wipe down.

Or, just put any liquids etc into a plastic secondary containment - that's what I do.