I am continually festooned with pens. I carry my Lamy Safari and Pilot Metropolitan in a pouch in my bag, If I think I'll need them. But I can always be counted on to have a Pilot Techpoint 5mm, a fine Sharpie marker, several pencils, and anything else I've purloined from doctors offices, hotels, restaurants, whatever. Basically the only pens I won't pocket are Other People's Pens (OPP).
I don't do ballpoints, they've never really worked for me, but since my bag is a black hole for writing instruments in the same way that some women's purses are hordes of lipgloss, I can generally find something appropriate for the task at hand.