Apple Headphones with Mic Low Sound/Volume After Months of Normal Use

Hi,

Has anyone else had this issue?
You have a 3rd Gen iPod Touch. You've got the factory white headphones with mic and volume control. You have EQ off, Sound Check Off, but you've set the Volume Limit setting to about 4/5 of the way from Max to protect your self from unexpected Volume blast that can occur if say your kid turns it up on you without noticing. I've used the thing to lesson to music and watch movies frequently, then 6-9months later you find yourself having to slowly increase the volume up to get the same level of sound? Now if you swap in a different or new pair of headphones (with or without jack; all Apple brand) the sound is noticeably louder.
I took the the headphones into an Apple store and told them the issue. They were able to hear the difference too when new head phones were inserted. They gave me a new set of headphones with mic and I swear 4-months later I'm in the same boat. Now my iPod is off warrantee and I'll have to shell out some money for some new Apple headphones or something else. Are these new headphones with the mic's junk or is it possible something in the iPod is slowly destroying these things? Not sure what to think here.

Yes I use the volume control and button feature of the headphone a lot!