There are two aspects for 'grading' a set of head-phones, comfort and electrical ability. If you think you may wear them for very long then comfort is definitely a biggy! I've found that head-phones that rest on my skull, -around- my ears not on them, are more comfortable than the other type (sits on your ears).
The other part, the electrical thingy, involves how well they reproduce sound (fidelity) and impedance matching to the receiver's audio output. For typical voice reproduction a huge frequency range just isn't needed. For music yes, voice no.
So, who uses head-phones for long periods of time and what kind do they use? There are a lot of professions that do that sort of thing, pilots, coaches, almost anyone around noisy equipment, whatever. Those type of 'cans' are more expensive than others, weigh more, but you can wear them longer before ripping the @#$ things off and stomping them, you know?
Best method for finding what's 'right' for you is to try them. That's also going to be the hardest way of doing it. Oh well...
- 'Doc
Good approach.
Here is another list...
Open back/closed back: Open=cooler to wear? Better frequency response? (debatable?) Closed=better acoustic isolation both inside and outside the headphones. (fact)
On the ear/over the ear/ear buds: On the ear=lighter, but less comfort; Over the ear=Bit heavier but better acoustic isolation, generally more comfortable; Ear buds=not discussed so far; wide range of prices and performance. How suitable for SWL?
Single cord/two cords (one for each "can"/channel): single cord=more convenient. Single cord allows quicker ID of left/right (if that matters with SWL)
Cord length and thickness and coiled or straight: Thick cord more durable; thinner cord less cumbersome; Shorter cord less cumbersome; longer cord if you do more extended listening leaning back away from the radio. Coiled/straight: ???
Cord detachable (plugs into headset): Detachable=easy to replace defective cord or to install a longer/shorter/different type cord.
Wired/wireless: Wired=less likely to interfere or conflict with SWL; wireless often shas ome audio artifacts, some worse than others; some barely perceptible.
Type of material touching head - vinyl, pleather, leather, cloth: from least to most comfortable.
Now someone can give us an "electrical/internal component" evaluation: a list of diaphragm and driver technology and material options, pros and cons.
Going into this, I didn't realize there were so many variables. If I were getting a set ONLY for SWL, I wouldn't spend more than $30 because the frequency response doesn't need to be extended - but many may want to spend more for more comfort and better durability. If the headphones are for combination use, including music, I feel I need to spend over $50-$100 to get a decent set.