The reality is, there's no way for you tell, even if it changed. Humans can barely remember what something actually sounded like 5 seconds ago. You can easily do that test with a friend, a snippet of a recorded signal, and a simple EQ. Play something through the EQ and have your friend change the settings. Then have it played through it again, and say if there was a change, and what kind of change, and how drastic the change is. Unless you're super human, you won't be able to tell with any reliability at all. Now do that while increasing the time between tests. Wait a day, a week, a month, 7 years, and look if you can with any reliability tell the difference. I'm gonna spoil it for you and just say, you can't.
If you want a scientific explanation, look up Manfred Zollner. All his work is in german, but it doesn't get more scientifically accurate and reliable as this. Your browser and Youtube can translate most of it. But you can also take my word, as I have looked through the stuff regarding this topic: There should be no difference in sound, unless potentially your electronics are failing in an incredibly abnormal and weird way. But that should be fairly obvious.
This could be an explanation though, since an increase in resistance with the electronics, could remove some top end, which to you might sound like it has more low end, while in actuality the signal just lost some meat. Though I find that unlikely.
Edit:
And as others have mentioned, you lose your hearing with age. The very sizzly top end goes down (20k for some young children with very good hearing, I have 17k at 23, many people with 60 have less than 15k). But most people also lose around 4k (which is a lot of the range in human speech, hence why people have trouble understanding others at high age). Those can both contribute to everything sounding warmer and deeper. It's not actually an increase in low end, just a loss of top end.