I found the following words of William Barclay challenging:
"Often we find ourselves with a small amount of time; and often we know that there is something which ought to be done; and often we say, 'It's not worth beginning with so little time available.'
It is a dangerous phrase, because it means that the half hour is wasted--and wasted half hours soon mount up to a considerable amount of time. If we work a five-day week and waste half an hour each day that is two and a half hours. Over a year that is one hundred and thirty hours; and one hundred and thirty hours is not much short of a week--a whole week's time and work wasted and gone. - From Daily Celebration, 1971, p.172