Technology changes things. The five most monumental revolutions in information technology have arguably been the printing press, the computer, the Internet, the personal computer, and the smartphone.

Credit for the smartphone goes largely to Apple and the late Steve Jobs. This year marks the iPhone’s 10th anniversary.

The iPhone wasn’t the first smartphone, just as Johannes Gutenberg’s wasn’t the first printing press. But both were far better than anything before.

What Jobs did was combine the technology of the existing iPod portable media player with that of a cell phone, portable Internet device, digital camera, and personal information manager in a user-friendly package that had the keyboard not separate but integrated into the screen.

The iPhone in turn transformed Apple Inc. into the world’s most valuable company, with a market cap today of nearly a billion dollars.

Famously in 2007 Steve Ballmer, then Microsoft’s CEO, emphatically predicted that Apple’s new phone would fail. He contended, “There’s no chance that the iPhone is going to get any significant market share. No chance.”

Ballmer was at the helm of Microsoft when it designed its then current computer operating system, Windows 8, to look like a smartphone operating system in order to promote Microsoft’s own smartphones and tablets.

All three failed in the marketplace, with the unsuitability of Windows 8 as a computer operating system being a key factor in the decline in the popularity of desktop and laptop PCs, leading to billions of dollars in losses throughout the industry. With Windows 10, Microsoft has since returned to providing Windows computers with a computer operating system.

One of the key factors in the success of the iPhone was Apple’s introduction a year after the original iPhone of the App Store, which let users install small programs or apps from other companies. This helped the iPhone leapfrog past competing smartphones from BlackBerry, Nokia, and Microsoft. Today the App Store provides access to more than two million apps, many free, many others at relatively low cost.

The word affordability can’t be used about the iPhone itself. With few exceptions, it has steadily increased in price. The next iPhone is rumored to be a $1,000 device. But people have paid the price, supporting Apple’s huge profit margins. Since 2010 iPhones have represented the single largest source of Apple’s revenue, surpassing computers, tablets, and other sources.

The iPhone has evolved significantly since its inception. The first iPhone had a screen of 3.5 inches and a resolution of 163 pixels per inch. With the two most current models, the iPhone 7 has a screen of 4.7 inches and a resolution of 326 pixels per inch, while the iPhone 7 Plus has a screen of 5.5 inches and a resolution of 401 pixels per inch.

The iPhone’s main competition these days are Android smartphones. They’re made by different manufacturers, from Samsung to HTC, with the common factor being the Android operating system from Google. Since 2010 more Android phones have been sold each year than iPhones, though Apple remains the single most profitable smartphone manufacturer.

The iPhone, however, has experienced a bit of a slump lately, with sales uncharacteristically slumping compared to previous years, held back by its lack of major recent innovations and by inexpensive Chinese competition.

Apple is hoping that its next phone, the iPhone 8, which is scheduled for release in September 2017, will restart its upward climb. Along with its sky-high price, it will also likely be bigger, thinner, and lighter and feature wireless charging, and it may or may not have an edge-to-edge screen without a home button at the bottom.

Not everyone, including diehard Apple fans, will want to pony up a grand even when spread out over time. Other options exist to improve the experience you have with your current phone.

If your iPhone is getting long in the tooth, sometimes the single best option to refresh it is to replace the battery. Smartphone batteries can begin losing their ability to keep a charge after a couple of years, forcing you to recharge sooner and sooner. It can cost only $60 to have a local phone repair shop do this for you. If you do it yourself, it’s cheaper but riskier.

You won’t be able to add to the internal storage of your iPhone or swap it out for larger storage. But if you’re running out of room for videos, photos, or apps, you can add external storage such as a SanDisk Connect Wireless Stick or an RAVPower FileHub Plus.