Preventing cat urine damage

[Alison Cummins]

I own and live in a pretty triplex with four rental units, built in 1928. 

One of my long-term tenants moved out. I installed new hardwood flooring in her unit and restored and shellacked the woodwork with the expectation of tripling the rent. So far the best applicant for the apartment is someone with a small dog (I can live with scratched floors)... and a cat. Two of my other tenants have cats and I'm not overly worried about them because they're clean and tidy, their floors aren't new and the woodwork is painted. If a cat pisses on the baseboards I expect them to be salvageable. If not I have scraps of baseboard to patch damaged spots. 

But in the new place, the floor is new and the baseboards are shellacked. Is there a way to prevent cat smells from stinking it up permanently? A young, healthy cat with a clean litter box won't piss everywhere, but young cats get old and healthy cats get sick. 

The prospective tenant has offered a pet deposit (it's illegal to require one in our jurisdiction). I could use that to pretreat the baseboards with ZIN primer if that made sense. 

Any other thoughts?