Plenty of breeds would happily settle on a ground-floor bed and do the stairs twice a day. This one will not. Welsh Springer Spaniels are documented as Loyal and score 2 out of 5 on alone-time tolerance, which in practice means the dog goes where you go. In a house where the kitchen is on one level, the living room on another and the bedrooms above that, following you is not two trips a day — it is fifteen or twenty.
Baltimore's staircases make each of those trips harder than a suburban flight would be. A twelve-foot-wide house forces a steep rise and a shallow tread, which loads the hindquarters more on the way down than on the way up. None of this causes hip dysplasia, which is inherited. It does determine how early a marginal hip starts hurting, and how much of the dog's twelve-to-fifteen-year lifespan is spent comfortable.
The interventions are cheap and structural. A second bed and a water bowl on the floor where the household actually spends its evenings cuts trips substantially. A runner on the treads gives a dog with feathered feet something to grip. And the marble front steps, iconic as they are, are genuinely slick in rain — worth a moment's care with a wet dog coming home.