I don't because I don't have an Equalizer, except the crappy one on my iPod. But for me, the decision to EQ or not is, itself, colored by the presumption that things are pleasantly flat and full to begin with. I feel no duty to avoid EQ. I believe that if things were truly flat, EQ would be undesirable. But I challenge anyone to find me a speaker or a headphone with a flat frequency response. The point of EQ is to "equalize" what isn't equal.
I agree with the view that the best EQ is having everything doing what it's supposed to be doing. But if you can't change room dynamics, or your equipment spikes and dips in certain frequencies, why wouldn't you want to equalize the situation. The problem with EQ is that it's another layer of artificiality. I don't need the extra hum. I don't want any extra issues of phase. Still, I'm going to use what I can to get a sound that appeals to me. On my M^3, there's a variable bass boost. That, in its own way, is a limited form of EQ. On some tracks, the recording is so bass shy it needs a little help. On the other hand, there are some recordings that need a little less.
One of the added wrinkles is the degree to which recording engineers do different things in the studio than their counterparts did three decades ago. It's not just a difference of technology. Recording engineers are using a lot more compression. They are recording at insanely loud levels, which creates its own havoc when the settings are all different - in the recording itself. My whole system is based on the hope, wish, dream and ideal of getting - in my living room - what the artists, producers and engineers were going for in the studio or on stage. But I'm still the master of my own domain (snicker, snicker) and I know what I like. When the music is too loud, I turn it down. When the bass is anemic, I crank it up (if I can). When the bass is too prominent, I try to tone it down.
I see nothing wrong with taking an honest assessment of your headphone's limitations and making whatever adjustment you need to get the right sound. If that means tinkering with the EQ, that's fine with me. On the other hand, most of the processing on my main stereo and my M^3 goes untouched. Most of the time, those special circuits are made to sell equipment to the easily impressed. Most digital EQs and other special processor tricks I've seen produced changes I didn't want. My only interest in adjusting the dials is to correct something I couldn't correct any other way.
,Equalisation being something that should have been done correctly in the 'producer' mastering stage of recording music .
