I have several MMCX and 2 pin IEMs. I've never had one fail on me. I've had one MMCX that cut out occasionally but I was able to replace the cable and that seemed to fix it
I think the biggest risk is connectors loosening over time, but if you don't disconnect them often I think they'll last a long time.
Another question for anyone who knows: is the socket the pins go into usually part of the plastic shell, or is it a separate component that can come loose?
It depends on the IEM but it's often a separate bit, this does mean it can sometimes be replaced if it breaks, although many IEMs this would be quite involved, possibly involving a full re-shell. Some IEMs can be disassembled and put back together, glued faceplates are common for example, or IEMs that separate into two parts which are glued together. Some use screws. There are modders who take apart IEMs routinely.
I wouldn't be overly concerned about it, but I would be moderately careful as well. I do have a policy of not frequently disconnecting and reconnecting IEM cables, that does wear them out and they can become loose.
Some 2 pin designs are worse than others, flush can have issues but there are some like the Symphonium Helios where it's a flush 2 pin on the end of a stalk, this virtually guarantees you are going to bend the pins. Also while some IEMs (like the Monarch Mk2) are totally flush, others which look flush (Variations, Blessing 2) are actually slightly recessed and this slight recess probably does help a bit as long as you have a cable that mates properly with it (most 2 pin will, the vast majority of even flush 2 pin cables still have a slight rectangular plastic protrusion that goes into these connectors).
I have one each with the qdc, 2pin and mmcx ones and I have been using all of them on and off for a while. No issues with either so far. I'm most worried about the mmcx one because that's the one I see broken most anecdotally here. Don't know if it matters but I don't wrap cables while storing IEMs.
blah618 t1_j11ex7d wrote
the biggest issue with 0.78 2 pin connectors is it becoming loose and you losing one side of the iem
This is not helped by fake 0.78 pins that widen the connectors.
t2 ftw
strength wise there is nothign to worry about