Maybe you can afford to wait. Maybe for you there's a tomorrow. Maybe for you there's one thousand tomorrows, or three thousand, or ten, so much time you can bathe in it, roll around it, let it slide like coins through you fingers. So much time you can waste it.But for some of us there's only today. And the truth is, you never really know.

This quote is saying that some people have to take advantage of the time they have now, because they might not have the same luxury of time tomorrow. People who have the luxury of waiting might have enough time left to do whatever they dream and waste time, but some people have only have today and never know when “tomorrow” might never come. Therefore, taking advantage of the present should be taken seriously, because it can quickly become the past.