Time was, I drank coffee more by the quart than the cup (or by the liter rather than the cup for my metric-using friends). When I was an undergraduate, for instance, and worked in the campus coffee shop, I drank espresso like it was drip coffee, and I could knock it back by the cupful and go straight to sleep. As a graduate student, I would drink the bitter black brew–for I stopped taking cream or sugar in my coffee before I started driving–as long as it was ready to hand, which was most of the day each day. My consumption ran at times to multiple pots in a day, and I remember one day that I was into double digits.

Photo is mine.
Now, I am aware that I was not the smartest in doing so. My body served to remind me of it at times then, and I am chagrined at my youthful follies independently of those reminders now. The idea seemed good at the time, of course, else I’d not have done it–but so did various bouts of drinking that left me puking down stairwells or falling down them, and so did provoking arguments that left me sprawled on the floor against the opposite wall from where I had begun. (Clearly, I have not always had good judgment. Perhaps I have not often had it.) I felt I had need or would benefit–or both, as when I finished drafting my dissertation more than seven years ago, now.
Consequently, I have reduced my intake a fair bit. Rarely do I drink more than a pot in a day, anymore, though I seem most days to drain a pot or its equivalent. And I seem to drink it more slowly than I used to; even a year and a half ago, I would drink three cups in the morning before heading out ton work, but now, I drink only two. Nor is it the only thing I seem to do less swiftly now than before, though the list of such things is longer than I care to recount at the moment. (It is also not universal; there are some things I do faster now than before. Typing is one. I suppose the persistent practice is helping.) And I find that that is somewhat worrying.
As I write this, I am in my mid-thirties. I can anticipate a long life ahead of me, still more of it than has already passed. If I am slowing now, then I would expect that I will slow more–and, paradoxically, more rapidly–as I move through the remainder of my life. At some point, I would grind to a halt, and that might be the end of it, but if it is not…it is not a comfortable thing to contemplate. And even if it is, if I am at such a place in my life that things will get worse, and more worse than better, from here, surely that is also not a thing about which to be happy.
I have to hope that slowing down is not going to be a bad thing for me. But what I have been able to do, I have done because I can do things quickly and well. Losing part of that does not seem like it has much good in it.