Novice and skilled golfers took a series of golf putts with a standard putter (Exp. 1) or a distorted "funny putter" (consisting of an s-shaped and arbitrarily weighted putter shaft; Exp. 2) under instructions to either (a) take as much time as needed to be accurate or to (b) putt as fast as possible while still being accurate. Planning and movement time were measured for each putt. In both experiments, novices produced the typical speed-accuracy trade-off. Going slower, in terms of both the planning and movement components of execution, improved performance. In contrast, skilled golfers benefited from reduced performance time when using the standard putter in Exp. 1 and, specifically, taking less time to plan improved performance. In Exp. 2, skilled golfers improved by going slower when using the funny putter, but only when it was unfamiliar. Thus, skilled performance benefits from speed instructions when wielding highly familiar tools (i.e., the standard putter) is harmed when using new tools (i.e., the funny putter), and benefits again by speed instructions as the new tool becomes familiar. Planning time absorbs these changes. (Contains 5 figures and 2 tables.)