Piper Jaffray analyst Gene Munster has been predicting for four years that Apple (NASDAQ:AAPL) will launch its own television set. One of his most recent failed predictions for an Apple-branded television was that the company would launch one at the end of 2013. But as Apple Watch rumors took center stage headed into 2014, Munster has since backed off his predictions for a TV in the near term. But headed into 2015, Munster is back with another timeline for Apple's TV.

Apple TV set top box. For years, rumors have circulated that Apple could introduce an Apple-branded physical television. Image source: Apple.

Apple television in 2016?
This time giving himself an extra year, Munster thinks Apple will launch a TV in two years.

"Well, this is part of my annual penance of being incorrect on the time. We really have to go back and look at where we got it wrong," Munster told Business Insider in an interview. "I think we just missed a very simple take -- is that Apple takes a long time in between products."

Munster went on to explain that the company has taken three to six years between major product launches over the past decade.

"And so, ultimately the Watch is what hit this year, they're gonna' refine that next year, along with payments. And then that probably gets us into 2016 more of a time frame for the actual television," Munster said.

Munster believes there is significant opportunity for Apple with a TV, enough that it could grow Apple's business by 5% to 10%. He believes an Apple TV could be priced around $1,500 and that Apple could capture 10% of the 220 million TV units sold globally every year.

Is an Apple TV really a good idea?
In the Steve Jobs biography published in 2011, author Walter Isaacson wrote that Jobs not only wanted to revolutionize TVs, but also had made progress in developing an innovative approach for a TV.

And he very much wanted to do for television sets what he had done for computers, music players, and phones: make them simple and elegant. "I'd like to create an integrated television set that is completely easy to use," he told me. "It would be seamlessly synced with all of your devices and with iCloud." No longer would users have to fiddle with complex remotes for DVD players and cable channels. "It will have the simplest user interface you could imagine. I finally cracked it."

So it's not entirely farfetched to predict that Apple is considering building a television.

But investors should still approach any predictions about an Apple TV with skepticism. Not only is Apple known for putting product plans on the shelf or delaying them at the last minute, but it's also never certain that Apple will succeed as successfully in every product category as it has in those it has launched in the last decade.

Apple TV. Image source: Apple.

Further, Apple already has its Apple TV set top box. While its last refresh was more than two years ago, Apple CEO Tim Cook has said that the device is no longer just a hobby. And past rumors have suggested that Apple may be readying a major refresh that includes support for third-party apps and video games. Of course, even Apple TV set-top box rumors deserve a dubious eye. But the point is that Apple could opt to continue to focus all of its resources in the TV category on its set top box, and not get around to a physical TV for years -- if ever.

Speculative rumors about new potential Apple products should be given zero weight in investment decisions about Apple stock. While predictions about new Apple products may be entertaining, there are too many uncertainties surrounding such predictions for them to be useful. Four years of Munster's annual TV predictions never coming to fruition shows where relying on such rumors could potentially lead investors.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.