KUALA LUMPUR, Nov. 26 -- Not too long ago, trading in a used phone was an ad-hoc affair, often involving a bit of haggling at a small, independent store.

Today, a new generation of professional second-hand retailers like CompAsia, Swapper Malaysia, and CEX have turned the trade-in market into a booming, mainstream industry, fuelling a surge in smart consumer habits and, for some, providing a desperate financial lifeline.

This new, structured ecosystem is what brought 28-year-old digital marketer Viknesh Raj into a store last weekend. For him, upgrading is not a luxury, but a practical necessity.

"I shoot a lot of short videos, so my old phone just can't keep up," Viknesh said. "No point burning thousands on a brand new one when you can...