(CNN) -- The adage "size matters" doesn't seem to apply to smartphones.
Sales data shows high demand for phones with screens of all sizes -- from the compact 2.4-inch screen on the BlackBerry Curve to the beefy display on HTC's Evo 4G, which measures 4.3 inches diagonally.
The size of a handset's screen often takes a back seat to other factors such as marketing, software and carrier support, analysts say.
Yet many recent top-of-the-line smartphones, such as Motorola's Droid X and HTC's Droid Incredible and Evo, range from 3.7 to 4.3 inches -- and all three were big sellers. Samsung's Galaxy S line of Android phones all have 4-inch displays, and the company reportedly sold 5 million of them worldwide in less than four months.
"With a flagship product, you're going to see 4 inches at least," said Carolina Milanesi, a mobile-hardware analyst for research firm Gartner.
The average size of screens on phones shipped worldwide this year has been trending upward, according to a report by research firm DisplaySearch. The average display size of one type of screen technology used in the most popular smartphones grew 20% in the last quarter over the same time frame from the year before, said Paul Semenza, a DisplaySearch executive.
That phone makers are gravitating toward larger sizes may have little to do with what consumers say they want. Rather, manufacturers could be expanding dimensions to work around software constraints.
"They're trying to get more stuff on the screen," said Aaron Rattue, a technology expert for GFK Group. "In the mass market at the moment, you see this trend toward a much bigger touch-screen."
Rattue continued, "People aren't necessarily buying smartphones based on screen size. The sales tend to reflect what new products are coming out rather than a direct consumer need."
Milanesi agreed. "If the latest devices are the larger screens, then that's what people will buy," she said. "Is it the popularity of the larger screen, or is it the popularity of the device? I think it's the latter."
Traditional thinking would suggest a one-size-fits-all mentality would be a bad strategy for a manufacturers of any kind.
But Apple has done gangbusters with that approach, making its cellular division among the most envious and profitable of any. All four iterations of the iPhone have 3.5-inch screens.
Of course, there are limits on either end of the screen-size spectrum.
The last year saw the resurgence of "the mini" phones among some sectors of the market, especially with young people and women in Asia, Milanesi said. But tiny phones haven't performed especially well because few people want to hold something the size of a Milano cookie to their ears.
Likewise, very large phones such as Dell's Streak were largely seen as flops. At 5 inches, good luck fitting that beast in your pocket.
"The Streak underperformed," Milanesi said, "which was not really a surprise for us."
She added, "It's very difficult -- unless you have humongous hands -- to get from one corner of the screen to the other."
As for touch-screen tablets, the sector is so new that it's hard to predict.
Among dozens of Android and Windows tablets on the horizon, many are going with 7-inch screens. Android head Andy Rubin demonstrated a new tablet, which Google is collaborating on with Motorola, that appears to have a screen larger than that.
The PlayBook, from BlackBerry maker Research in Motion, will have a 7-inch screen. While company President and Co-CEO Mike Lazaridis called it "the perfect size" on Tuesday, he confirmed that RIM is also experimenting with other dimensions.
Apple's iPad, which is credited with practically inventing the category, has a 9.7-inch display. Three million were purchased in the first 80 days of availability, Apple reported.
In the company's most recent earnings call, Apple CEO Steve Jobs said 7 inches "isn't sufficient to create great tablet apps." He joked that users would need to sandpaper their fingers to use the smaller gadgets comfortably.
"We think the 10-inch screen size is the minimum screen size required to make great tablet apps," he added.
Seven-inch tablets "will sell," predicted Milanesi, the Gartner analyst, but "there will be compromises."
"If you want a true tablet experience, 10 is what you want," she said.