Have you heard the parable about the Tortise and the Hare? They were running a race. The hare dashed off, but quickly tired, whereas the tortise plodded along at a slower pace without stopping, thus winning the race. "Slow and steady wins the race."
Also related, "A stitch in time saves nine," meaning that if you take your time and do the job right, you won't have to go back and redo it.