Just my opinion... The only thing that I'm concerned about with mods are the set bonus, with a priority of speed secondary ONLY if possible. Most content is so much easier with 5pip mods of any kind, of the right set, leveled to 15. Sure, the 500+k I've spent to level up a Potency Arrow mod with Crit Avoidance as a primary isn't optimal, but I've passed it down for months. At the time it helped me crush whatever event I needed it for on a toon I didn't care for much for.
Now that I have about 40 full sets of 5pip mods (that's about 250 mods) I can start to be picky and switch the better ones to other toons, while passing the less than optimal primaries to others, like fleet crew members that I don't use anywhere but fleet battles.. While others may disagree with this strategy, farming and waiting for the perfect mods while content passes me by is not my plan, but will save you a ton of credits for sure. Also, I can now be much more picky about the mods that I keep and level up, because I have plenty I can move around.