To build on this: Duty Officers are an optional system, but they're a lot of fun (most important), are a source of XP, buffs, items, and Dilithium. Selling your Duty Officers lowers your ability to play the Duty Officer Assignment successfully, since you never know when a particular DOFF or set of traits will be useful.
I would not sell the Duty Officers on your main playing character. Now, if you had an alt, that's something else entirely. I've got one alt whose sole purpose in life is to recruit DOFFs and sell them on the Exchange. That's it! I check him once every few days and that's it.
Now, if you're playing with Duty Officers and doing content that earns you Dilithium? There's a way to make EC from that! Earn Dilithium, buy Zen, then buy Master Keys and/or Fleet Modules to sell to other players on the Exchange.
Find what works for your time/schedule and playstyle. It'll make it a lot easier, and more enjoyable.
How is doing missions you don't even get to activley participate in any fun? might as well play a board game or something. You guys are really making people miss out on easy money by making people think they have to do doff missions when they don't.
Duty officers (except for active ones) are exchange fodder to make money off of people that don't realize that ignoring this system in no way limits your gameplay experience, nothing more.