If you can run 5 days a week (both physically and logistically) then great! It'd be better to run 2 days, rest 1, run 3, rest 1, rather than run 5 rest 2 (in my opinion of course).
I currently run 3-4 times a week, though usually 3, and my improvements have been fairly steady since I started. I keep meaning to build up to 5 days a week but haven't worked it out to fit in properly with the rest of my life just yet
