stitch in time, a
A prompt action will avert more serious trouble. For example, Changing the car's oil every 7,000 miles is a stitch in time. The complete form of this adage, a stitch in time saves nine, appeared in Thomas Fuller's 1732 proverb collection, Gnomologia, and is so well known that it often is stated in shortened form. Ogden Nash played with it in the title for his verse collection, A Stitch Too Late Is My Fate (1938).