Is perfect efficiency really a good thing? I don’t think so.

A balloon is perfectly efficient immediately prior to bursting. The balloon is containing the maximum amount of air it can hold—it’s maximally efficient. But how long can the balloon remain in that state? At maximum efficiency the integrity of the balloon’s material is under the most pressure it can bear. The material begins to break down. It’s actually always in the process of breaking down thanks to entropy.

Either the pressure must be relieved or the capacity increased or the balloon explodes. The balloon must be handled very delicately when under maximum pressure to avoid rupture. Once stretched to capacity it is weaker from the stress and may not survive the same maximum pressure again.
Your business is the same. If your goal is 100% efficiency, you are pushing your resources to the bursting point.
Slack time is good time. Of course you do not want too much slack time but you do want some. Slack time gives time to think. Slack time gives time to expand or release pressure if you are approaching maximum capacity.
Too many managers think every moment must be filled with activity and productivity to achieve efficiency. Slack time actually demonstrates efficiency! If you have too much slack time, by all means utilize some of it. Cross train or build buffer. But remember that equipment and people benefit from the relief of pressure. It’s during “half time” that great plans are adjusted. Every moment need not be filled.
This is one reason so many businesses lack creativity. Nobody has time to think. Nobody has time to try new ideas. Too busy does not belong in your vocabulary. I often hear, “I’m sure there’s an easier way to do this but I don’t have time to play with it.” Depending on what “it” is, there could be a great opportunity awaiting “play” time. I would cherish employees that saw improvement as play time.
Lastly, measuring the business by productivity and efficiency puts the focus entirely on the wrong thing. Sales and margins are first and far more important that efficiency. Chasing efficiency will cause you to take your eye off the proverbial ball. Sales is the ball. If sales are falling you cannot fix the business by improving efficiency. Fix sales.
Shameless Promotion: Your business can benefit by rethinking objectives. Start with FOCUS. I can help your refocus. Do you allow play time? You should.
Chris Reich, Author of TeachU’s Business Talk Blog