You may have seen this before:
This is why you shouldn't interrupt a programmer: http://t.co/K2dNXKzjem— Jason Heeris (@detly) October 28, 2013
Flow state is important for developers – possibly more important for some individuals than others. If nothing else, sometimes it’s nice to block out random noises of the day.
Some important factors I see for developers choosing IEMs (in-ears monitors) or headphones are isolation, comfort, convenience, safety, and sound quality.
If your primary goal is blocking outside noise, you’ll want to examine the isolation capabilities of your device. A 3dB decrease of ambient noise is a halving of volume!
This might be obvious, but too much isolation could be a problem, if you want to hear certain things (teammates chatting, alarms, etc.).
If you’re wearing something for many hours, comfort is important. Comfort is an individual thing. Some many find IEMs more comfortable then headphones, while others may loathe the idea of having something in their ear for an extended period. The mass and clamping force of headphones may be a bother to some.
You’ll need to make your own determination here.
IEMs can be more convenient from an overall size standpoint, but there may be some cleaning related maintenance associated with them. Headphones are larger, but may have less cleaning maintenance. Also, headphones may be more convenient if you need to frequently remove them.
Listening too loud can damage your hearing. That said, having better isolation may allow you to listen to music at a lower volume, if the goal is to block outside noise.
Also, foreign bodies in your ear can also cause health problems, ranging from annoying to serious. Different people may have different tolerances to having IEMs lodged in their ears for extended periods – don’t exceed yours. Also, if you’re an IEM user, regular cleaning of your IEMs is probably a good idea.
This might be a lesser concern if music is background to your work. I’m not suggesting it doesn’t matter, but, it’s ideally good enough that it isn’t bothersome. If you might do some critical listening, though, keep that in mind.
Bonus: Built-in microphones
If your device microphone(s) aren’t good enough, a microphone built into a headphone cable or similar is probably a poor substitute for a better microphone. It might be useful for a smartphone scenario, but, I can’t really speak to that personally.
It’s up to you
You’ll need to make a decision on what’s important for you. How much do you want to isolate yourself from the world? Does your body respond well to having something in your ear all day?
Hopefully this helps you on your quest for the best set of IEMs or headphones for your needs.