Deadheading stops seed production which inturn releases
the energy back into flower production. This is one
reasons sterile hybrids are so heavy bloomers no seed production to slow flower spikes.

When most or all of the flowers on a stem have bloomed, cut the whole stem off of the plant. On most varieties of Red Hot Sally (Salvia spendens) the stem that holds flowers is reddish and clearly different from the green, growing parts of the plant that you don't want to remove. This really isn't necessary, but it makes the plant look nicer, which is the reason you are growing them in the first place. I pinch mine off the plant, but you could use clippers instead.

so, just to be clear...if i clip, pinch or cut of the whole red flower that is beginning to fall off and has faded, i will not have a flower at all for a period of time until another grows back, correct?

I had the same question and have been pulling the individual pieces but that doesn't look right either.