As investors, we're often told to find a "school" or "method" we like and stick with it. Cheapskate coupon clipper? You're a "value investor." Did you just know that Apple's (NASDAQ:AAPL) iPod was going to be a mega-success? You're a "growth investor." Prefer it when people show you the money? You're a dividend gal. Looking to get into steady, growing firms before the big institutional money can? Then you need to be in small caps.

I respect the urge to specialize. In theory, I'm all for consistency, as I really believe that a structured framework for investment decisions will give you an edge in the long run.

But as investors, we need to be careful that our doctrines don't become dogma. Put up hard boundaries, and your returns may not be all they could. Ask me how I know.

"How do you know?"
Because I watch my portfolio. And I watch what I don't buy, too. And that leads me to conclude that too much discipline can be a bad thing.

I'm pretty cheap. I consider myself primarily a value and cash flow guy. I get most of my big winners after the street turns on healthy, profitable businesses. I bought Nokia (NYSE:NOK) when a short-term sales bungle caused the street to discount it to the point where any value investor would have been drooling at its normalized cash flows. I keep companies like Johnson & Johnson (NYSE:JNJ), ExxonMobile (NYSE:XOM), and Intel (NASDAQ:INTC) on my wish list because I have a great appreciation for steady behemoths, at the right price.

But that kind of dogma costs me money. Case in point: Motley Fool Stock Advisor pick Netflix (NASDAQ:NFLX).

As a longtime customer, I know it's the best home-movie service in the industry. Heck, it invented its own industry. As a Street watcher, I saw the stock get chopped mercilessly last year, losing about 80% of its value. As a critical thinker, I figured that a major reason for the beat-down -- fear of competitive pressure from Wal-Mart (NYSE:WMT), Blockbuster, and others -- was overblown.

Did I buy it? No. Why not? Cash flows didn't support the stock price and they weren't predictable. Did I think it was a smart buy anyway? On many levels, yes. I thought the odds were that future cash flows would support a much higher valuation. But betting on things I can imagine, but don't see, doesn't fit my dogma, and I threw it out of the pile.

Step away from the calculator
You know who did buy it? Fool co-founder David Gardner. Better yet, he suggested that others do the same, making it a Stock Advisor pick when it was down, but not out. If you got in during the carnage of January 2005, when he re-recommended it, you've seen a mere 80% return. Even if you got in early on his November 2004 recommendation -- before the falling knife had stuck in the ground -- you'd still have seen a 50% return in a bit less than a year.

Let's get real: Not every stock performs this well. When you invest by gut feeling -- as is inevitably the case with a Netflix investment thesis -- sometimes you get a gut ache. Keeping with our gastrointestinal metaphor, Krispy Kreme, another Stock Advisor pick, has yielded nothing but pain. It's down 85% from when it was picked. Stuff happens.

But overall, Stock Advisor picks have posted total average returns that absolutely whomp the overall market. (They whomp mine, too, which is never an easy thing for a proud Fool to admit.) With real returns of 56% and 68%, freres David and Tom Gardner are beating the S&P 500 index by 38 percentage points and 50 percentage points, respectively, since April 2002.

Agnostic about opportunities
How do you explain those kinds of great returns -- which trump the already market-beating performance of our more specialized premium services? I think it's because Stock Advisor invests without limits, without dogma.

It's agnostic. We Fools know there's more than one way to get to our goal -- financial independence. As such, Stock Advisor doesn't suffer any arbitrary boundaries. No good company is thrown out because of market cap, growth rate, industry types, or even geography. The only requirement is above-average opportunity.

If Tom "Hidden Gem" Gardner sees great value in a famous, largish, mature athletic-shoe maker like Reebok, he recommends it. If David "Rule Breaker" Gardner sees opportunity in a stodgy old German carmaker or something as mundane as the original gas 'n' gulp, 7-Eleven, he'll bring it to the table.

The Foolish bottom line
Stock Advisor's returns speak for themselves, but better yet, its go-anywhere, do-anything stock-picking philosophy is a good fit for investors who don't want to be shackled by arbitrary rules. Small caps, value, growers, and underappreciated slowpokes -- you'll get it all.

And investing without artificial boundaries is not only good for your portfolio, it's good entertainment. You get to watch the brothers slug it out every month, and you can get a front-row seat via Stock Advisor's dedicated discussion boards. The gloves are off, no holds are barred, and no matter which one of them comes in second, you'll be the winner. Still skeptical? Try it for a month free, and we'll even toss in our recent Blue-Chip report.

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Seth Jayson hopes to juice his own returns with a little more agnostic opportunism. At the time of publication, he had no positions in companies mentioned here. View his stock holdings and Fool profile here. Fool rules are here.