Well, it depends what kind of salvia.
Salvias bloom mostly spring and fall here but not always. For example, salvia black and Blue, guarantica, and several others bloom all summer. Deadhead and they are fine (they are fine even without, but look better deadheaded). There are even fall only blooming salvias.

Annual salvia responds well to deadheading,

GGG

I have several planted areas of Blue/Black salvia and they are continual repeat bloomers summer to fall. I never deadhead them. BTW, hummingbirds love them.

Thank you. It's Salvia nemerosa Caradonna and is a perennial. It was gorgeous for about a week and now only has a very few buds and lots of old stems.