This is an old
carpenter's
adage. The meaning should be fairly obvious, being basically that of "Take extra time over the planning and the execution should go smoother".
Although originally devised by woodworkers, there is no reason that this saying doesn't apply to other trades, even (perhaps especially) to that of software development. Anyone who has ever taken any classes in formal methodology for software design will know that according to all the theories, they are supposed to spend at least as long designing their system as developing it. Yet how many programmers really sit down for weeks at a time with pencil and paper writing out flowcharts and modular designs?
Another nodeshell rescued FROM the evil clutches of the NRT