I read online that it is stain resistant and no sealing required.

As long as the cat has a litter box I can't foresee why there would be any urine - and I've read the stories of people trying to remove that ordor or stain.

As others have said, cigarettes are a different issue because nicotine odor and stains can linger and be a real problem.

Then I go after the stains and grease with specialized products.

Children's room might be better with a LVT because of staining.

Not worried about spills, stains or smells when tenants leave. 

Be sure to use a good primer sealer for the first coat though- depending on the paneling, the stain can bleed through pretty badly.

Assuming it is just some kind of stain, I would not fix it.

Typically the cabinets are stained, I get Sherwin Williams to color match the stain.I would never replace all the drawers and doors on a kitchen, the price is not much more to buy all new cabinets, by the time you paint or stain them, and you still have an old kitchen.

I've also seen stained plywood done nicely.