Nowadays, I just carry one at a time, unless I space out and put another one in my pocket. Hmm… what is it? A Pilot Explorer fine point, black - I always use fine points (I have to write little numbers in small places). Just like the ones our Landman uses - I steal his in meetings and he’s got to ask if he can borrow my pen; so I have to steal it again after I “loan” it to him.
Back in days that involved more selling I used to carry those matched Cross pen and pencil sets - but those were times when I was wearing suits and wining and dining and trying to be - well, you know, that kind of guy. After you bust a few Cross pens, you’re liable to decide they’re just not worth it.
But when I was in college, as Bally is now, I, too, packed an arsenal. Having a pallette available was useful in labs, and allowed for doodles of historic import. I approached the nadir of my learning effectiveness when I discovered calligraphy pens. Lecture notes became works of art (a little skimpy on guts, though).
Well, I recovered from that.
That was then and now is now.
Back to nowadays; yes, I carry only one. But I’m no longer a mobile beatle unit on a large campus. I use all manner of colored pens and pencils and engineering rules, templates, flexible curves and, uh, erasers. In past times everyone had their engineering rule and their template, etc. and stuck with 'em. People initialed their effects and if you roamed, as I do, much time could be devoted to looking for them. I got sick of that and ordered a dozen engineering rules, as many templates, a half dozen triangles and gobs of all colors of pencils and (bouncy) mounds of art gum erasers. And I scattered them throughout the office. They’re everywhere, every office, the conference table, the copy room, the kitchen - you’re never far from a vermilion pencil, or a carmine red or an engineering rule. My legacy.