Warren Buffett is in the news again, as the subject of a new, high-profile book: The Snowball: Warren Buffett and the Business of Life. He also recently graced the cover of Parade magazine in Sunday newspapers nationwide, accompanied inside by a list of "10 Ways to Get Rich" attributed to him. As a longtime fan of Buffett's, I found the list mostly on the mark -- except for his admonition to "never suck your thumb."

As we've discussed before, Buffett makes quick decisions. When you've got his decades of experience, you don't have to sit around and think about whether an investment makes sense. You just get whatever information you need and move forward. Or, as the magazine put it, you don't waste time thumb-sucking.

The cost of inaction
Taking action when opportunities arise can indeed be a smart move. Witness the investors who jumped into IBM (NYSE:IBM) around the summer of 1993, after its shares had been cut in half in the past year. They've enjoyed 18% average annual returns since. And consider those who bought into Cisco Systems (NASDAQ:CSCO) at $10 in 2002, after it fell from around $70 in 2000. It's more than doubled in value since then.

My own thumb-sucking has occasionally cost me plenty. I didn't buy into Genentech (NYSE:DNA), Anheuser-Busch (NYSE:BUD), or Nuance Communications (NASDAQ:NUAN) when I could have, and they're respectively up 11%, 47%, and 44% since I first added them to my watch list. I did a lot of watching and thinking with them (and many others), but never got around to actually investing. I was sucking my thumb.

(You maintain a watch list of stocks you're interested in, right? Setting up an online portfolio of your potential picks can help you spot compelling companies when their shares fall to tantalizing price points.)

Refusing to suck your thumb can also help you avoid procrastination. Why wait to fund a tax-reducing IRA for your retirement? Why hesitate to buy shares -- or sell them -- when you know you should?  Even Buffett has lamented some instances when he almost invested or reinvested in companies such as Wal-Mart (NYSE:WMT). Deciding to wait led him to regrettable results.

All that said, however, it can sometimes be better to suck your thumb than to take action.

Go to the movies
Even Buffett would agree. He's repeatedly talked about how he'd be happy with a stock market that only opened once a year. In his 1998 letter to shareholders, he essentially endorsed thumb-sucking:

The portfolio actions I took in 1998 actually decreased our gain for the year. In particular, my decision to sell McDonald's (NYSE:MCD) was a very big mistake. Overall, you would have been better off last year if I had regularly snuck off to the movies during market hours.

And when Buffett does make investing decisions, many people are content to lean back and follow his lead. If you're not confident in your investing skills, or you just don't have the time or inclination to dig deep into a company's financial facts, you may be better off letting smarter, more dedicated folks -- whether they're Buffett himself or the managers of top-notch mutual funds -- do the heavy lifting for you.

Where can you find such outstanding funds? Our Motley Fool Champion Funds newsletter offers a great introduction, and you can try it free for 30 days.

In the meantime, if you want to suck your thumb now and then -- in investing or otherwise -- don't worry. We won't tell Warren.

Further Warren-tastic wisdom:

Longtime Fool contributor Selena Maranjian owns shares of Wal-Mart and McDonald's. Nuance Communications is a Motley Fool Hidden Gems recommendation. Wal-Mart is a Motley Fool Inside Value recommendation. Try our investing newsletters free for 30 days. The Motley Fool is Fools writing for Fools.