Saying no is sometimes seen as a luxury that only those in power can afford. And it is true: turning down opportunities is easier when you can fall back on the safety net provided by power, money, and authority. But it is also true that saying no is not merely a privilege reserved for the successful among us. It is also a strategy that can help you become successful.

Over time, as you continue to improve and succeed, your strategy needs to change.

The opportunity cost of your time increases as you become more successful. At first, you just eliminate the obvious distractions and explore the rest. As your skills improve and you learn to separate what works from what doesn’t, you have to continually increase your threshold for saying yes.

Most of us are probably too quick to say yes and too slow to say no. It’s worth asking yourself where you fall on that spectrum.

If you have trouble saying no, you may find the following strategy proposed by Tim Harford, the British economist I mentioned earlier, to be helpful. He writes, “One trick is to ask, “If I had to do this today, would I agree to it?” It’s not a bad rule of thumb, since any future commitment, no matter how far away it might be, will eventually become an imminent problem.”

More effort is wasted doing things that don’t matter than is wasted doing things inefficiently. And if that is the case, elimination is a more useful skill than optimization.

I am reminded of the famous Peter Drucker quote, “There is nothing so useless as doing efficiently that which should not be done at all.”