Yes, if you want to hear it regardless if it's the induction mic or ordinary mic you are using.
My minidisc recorder has a bar that shows the recording level but it isn't very accurate so, if the recorder will allow it, it's best to listen to it while recording (or, at least, to set the level).
Once you have set it, you wouldn't need to monitor it any more, would you?
I forgot the headphones last year and ended up with several LOUD and distorted recordings and trying to compensate, several very quiet ones

.
I rather like the idea of replacing the headphone speakers with mics to make a binaural recording mic though.
The separation (same as between ears) does make a difference from what I have heard of those here.
I don't think I can do that in time for this year though

Gosh, that's induction mic, stereo mic, binaural headphone mic, headphones, recorder, discs and recorder to pack (and battery pack if you make one).
I reckon you can pick out a Mousebits member by the size of their backpacks
