Leo Tolstoy, in his short story, "Three Questions," said, "Remember then: there is only one time that is important - Now! It is the most important time because it is the only time we have any power." The easiest way to waste the present is to reminisce in the past or dream about the future. While those two pastimes have their place in the broad scheme of daily activities, it is important to be... present in the present.
Diaries. I maintain journals, periodically. But I hardly refer to them again. The exercise of capturing my life with words on paper is a useful exercise, to express joy or grapple with grief. Keeping these journals and carrying them around to refer to them frequently - not worth my time.
Planners. Long term future planners, timelines, etc., are useful to get a general idea of the direction your life would take in an ideal world. Experience is teaching me that my best laid plans are wishful thinking.
I'm not sentimental. But, I'm a visionary and rather enjoy planning and forecasting. My shortfall is dwelling in the future, mixing idealism with action plans. It's an attempt to control my future. A futile expenditure of my energy. Now, I know that wealth and riches are not what you own or how well you live. It's having ample time, freedom to spend that time as you see fit. The pleasure of living in now and using your time to work, sleep and enjoy the one thing given to all men in equal measure. 24 measures daily.