Do you find you need routinely to cut a particular frequency from the lead vocal (or whole mix) to keep the song from being too hard in earbuds? I find myself backing off 2.5-3K in the lead vocals. Obviously, you don't want to go too far with that, but the vast majority of listeners are going to be using some kind of earbuds.

I'm not sure I specifically cut that freq but I do test my mixes in four different sets of headphones/earbuds.

I have found it is the bottom end that needs the attention. Very low notes don't fair well on earbuds so I find that if I know the product is going to end up there I do some careful bass tweaking in the mastering stage to make it work. There is usually a point that the low end can satisfy both the earbuds and the speakers at the same time. Better quality ear buds should not be changing the midrange so much.

First thing I would do is be sure that you aren't destroying the careful mix you made for ear buds. Find a master album that you admire for both its content and the high quality of its sound that has a full range and see how it sounds on the buds. Do not do anything to the sound you get. This will be your reference in testing out audio gear.
 
If you hear problems it should be in the gear not in the album. The over all idea is after listening you should know where you stand with the buds. If the album sounds good on the buds you know its the mixes you are doing that have the problem. If on the other hand the great album sounds bad then you know if you adjust the mix it will hurt it. 
 
Personally, I think you should ignore ear buds. 
 

John is mainly correct, I would not sacrifice a mix just to make it work on earbuds. But having said that I want to refer to something that happened to me a few years back.
 
I was lucky enough to score a job where I mixed and mastered an Indonesian Pop Music CD. (Killer playing and it was all live, serious band folks and I mean serious, and the singer was amazing too) I was in Australia and I did it all by remote control working with the record label in Indonesia. It all went well and they loved the mixes except at the end they said it was not sounding quite right on earbuds.
 
And I thought why would you care about them and then they informed me that 99% of the target audience will be teenage girls using earbuds. Well then I thought OK I need to fix it. It was simple bass end issue and with some correction I was able to keep it sounding terrific on the speakers (large and small) but I got it sounding great on the buds too. 
 
So I guess the moral of the story is what is your target audience likely to be and will earbuds be the prominent listening medium. If so then I think you do have to factor them in a bit more. They are a part of life these days. Unfortunately so is the laptop speakers/phone scenario. But I don't get too concerned about them though.

No, if it was mixed and mastered correctly, it will play good on your ear buds and all other sound systems
 
Cj

The downfall of music are ear buds!

Jeff, I want your magic sauce. I can't get the bass to sound good on ear buds. On all my stereos the music is AWESOME! but on cheap junk earbuds it just disappears. Nothing I can do about it. Only thing I've considered is using an octave tool to duplicate the sound up an octave... but I've never gone that far.
 
I've definitely pushed the bass to the top of my comfort level on all my mixes to try to compensate.

I EQ and mix as I go predominantly on earbuds. I have several good headphones and monitor speakers as well.

I use the reference track(s) approach as well as mentioned above. That is very helpful to keep me from fooling my ears into thinking the mix is working, when it's not by comparison to the reference track.

I also use the Focusrite VRM box which helps reference what is and what is not working in the mix.

That all said, I use earbuds along the way as my working headphones. If the mix sounds good on earbuds I'm finding it sounds great on speakers, in the car, or on other better headphones. However the reverse is not always true. If it sounds good on good speakers or headphones it may not sound good at all on earbuds.

I use the earbuds with the reference tracks and with the VRM box quite often. I can get a lot done even at low volumes until I need to crank it louder. My one other upside (I hope) is that I may preserve my ears for future use by not enclosing them or blasting them for long periods. I'm hoping to hear and enjoy my music when I'm old - without a hearing aid.

CJaysMusic
No, if it was mixed and mastered correctly, it will play good on your ear buds and all other sound systems
 
Cj

I've always believed this to be true, so it's what I always aim for in a recording.