How to protect a suede blazer from DIRT? (Not water.)

[Imzadi]

I fell in love with a lovely suede blazer that was on clearance because it had a few dirt/soil marks on the shoulder & arm that it picked up from brushing against something dusty & dirty in the store. I tried as best I could to clean off the dirt marks but they are still faintly visible. So I know dirt embeds in it EASILY & doesn't let go.

How can I protect it further? I can't walk around afraid to rub against anything. I'm more concerned about dirt than water, as I tested it for watermarks (while cleaning it,) & it dries up fine after being wet, with no sign of any spotting.