Had to stop and go look up the etymology of heed. It's word that seems to get used a lot without people ever stopping, ironically, to take heed as to what it really means: it means "to pay attention, to give consideration to; to mind" but it came to Old English from the Old High German word huota which means "to guard".
We can't guard time, even if we can pay attention to it and give it consideration. It rushes on, regardless of us. We can't save it or take it or waste it or spend it: it goes of itself, it's not a currency we can bank on, despite our many human desires to force it to our service in some way. Whether we make good use of our time is one thing, but we have no control over it in the end.
I think I usually make pretty good use of my time, though it often slips past me and continues on its merry way when I'm distracted; when I'm busy (which is to say, often) and when melancholy. Reading, on the other hand, the kind of reading that absorbs you into a good story, seems to merge you INTO the flow of time. It passes but you pass with it, subconsciously aware and fully involved in its forward progress even while you detach mentally from the world time is passing through.
Mostly, I think, we are aware of time only after it has passed. It leaves us with whiplash from trying to look both backwards and forwards. What are nostalgia and anticipation, after all, but ways of trying to slow down or speed up time?
Spring and fall are the two seasons where we can mark the passing of time so much more clearly than summer and winter when the world often, for all intents and purposes, seems to be standing still. Some days, watching the slow-motion time-lapse of spring around me I can almost SEE the colors appearing and disappearing. Already the forsythia are morphing from yellow to green, just as the rapeseed spreads their neon-pulse across the fields. The crocus came up, went down, replaced by snowdrops and daffodils and wood anemone and tulips in turn; first cherry blossoms and now here come the lilacs, each giving way to the next in a slow-moving dance of color. The chestnut candles have yet to burst into pink- or white-tipped flame, but the wild white hawthorns are blooming now.
Time may give me no heed, nor you, but we at least can glory in the special effects its passing brings to beauty and rejoice that it continues. Time comes to pass. It comes to pass, not to stay.