Each year the new models were smaller, lighter and came with longer battery life.
Extrapolate the trends at the turn of the millennium and by now we should all be carrying wafer-thin handsets that are as light as a feather with a battery life measured in months.
But in 2007 something changed: Steve Jobs unveiled the iPhone. Twice as big, three times the price and much heavier than the competition, the iPhone ignored all of the trends in mobile phone design. While other phones were routinely exceeding a week of battery life, the iPhone struggled to manage a single day.
Despite its obvious shortcomings the internet-enabled iPhone with its 3.5in screen was a hit, instantly reversing 25 years of smaller, lighter, longer-lasting mobile phone evolution.
The trend for bigger, heavier phones has continued and with some handsets approaching six inches long, they're becoming increasingly impractical to use as a telephone.
Taiwanese monster-phone manufacturer HTC has come up with a novel solution to the problem of huge handsets: a small phone owners can use to call the oversized phone in their pocket.
It may sound like an April fool, but the technology is very real. The big handset – marketed as the HTC Butterfly in Asia and Droid DNA elsewhere – is a typical premium Android smartphone with a 5in, high-def screen and a top-notch processor to match.
Its baby brother is the HTC Mini, an attractive but fairly unadventurous-looking push-button handset with a monochrome screen that wouldn't have looked out of place with a £40 price-tag in the pay-as-you-go aisle a decade ago.
The two handsets pair wirelessly using a combination of NFC and Bluetooth. Wireless range is limited to around 10 metres, so both phones need to be carried together to work.
All of the basic features of the Butterfly are replicated on the Mini. Calls can be made, text messages received and calendar appointments reviewed, albeit in a less efficient push-button way than on a modern touchscreen.
The Mini also has a few other tricks. When the Butterfly is hooked up to a television the Mini acts as a remote, and when the Butterfly is in camera mode the Mini performs as a remote shutter release.
The HTC Butterfly and Mini combination is only available in China for now and HTC has no plans to bring the Mini to the UK, but if you're looking for the dual handset experience there's always eBay.
Positives A clever way to have a large handset for web browsing without looking like Dom Jolly.
Negatives Two handsets to carry, charge and try not to lose.