Zhang Yi is a dream customer for the world's cell phone manufacturers even though he is not loyal to any particular model of handset -- the 24-year-old student from Nanjing University has had nearly 500 cellphones in nine years.

Constantly on the lookout for new functions, "I still haven't been able to find one that really suits me," he said.

The journalism and communication student kept one cellphone for almost six months but ditched another one after just 12 hours.

His first cellphone was a present from his father in 1998, when few people were using mobile phones. It cost more than 8,000 yuan (around 1,025 US dollars) and was expensive to use.

"The phone had limited functions. To me it was only a pager and I got rid of it in less than two months", Zhang said.

In 1999, as simplified Chinese displays and text messaging became available, Zhang upgraded again. But his new cellphone didn't have any real choice of background colors and ringtones, so he swapped it for another.

From 1998 to 2002, he owned 14 cellphones.

With an array of new mobile phones appearing with sexy new functions, Zhang began changing his mobile phones much more frequently.

"I buy a phone I like on impulse, and then sell it again later on. At a rough guess, I must have lost several thousand yuan upgrading all the time," Zhang said.

Statistics from the Ministry of Information Industry indicate that China will have 520 million mobile phone users in 2007.

More and more people are buying a second mobile phone – almost 70 million in 2006. The figure is greater than the number of people who bought their first cellphone in 2005.

With China's fixed-line telecom operators expected to get 3G licenses soon, a survey conducted by CCIDData shows that 57 percent of cellphone users firmly intend to buy third generation (3G) mobile phones in 2007 and another 37 percent say they may purchase 3G cellphones. Cellphone manufacturers can look forward to another wave of sales as the new technology comes onstream.