Mr Mohammad Azahari Abdul Razak was less than 2g of heroin away from a death sentence when he was caught trafficking drugs in 2001.
Then 20, he was sentenced to 20 years in jail and 20 strokes of the cane.
Now 35, he started taking drugs from the age of 14 when his childhood friends introduced him to cannabis and pills. They would pool money to buy drugs and consumed them at a void deck.
At 16, he was arrested for rioting and sentenced to 18 months in jail, but returned to his old friends upon his release. At 17, he started taking heroin, working odd-jobs that earned him around $40 a day.
Then, he began selling the drugs. Not long after, he was arrested again for unlawful assembly and sentenced to six months in jail.
But it did not stop him from continuing his business in cannabis when he came out, and he moved on to heroin afterwards.
He was 18 when he was arrested a third time, for drug consumption. Central Narcotics Bureau (CNB) officers caught him and two others red-handed in his three-room flat, and he was sentenced to a year in the Drug Rehabilitation Centre.
The fourth and last time he was arrested, he was 20. He had started selling more heroin and was in a car with his partner when CNB officers intercepted them. "I could have been sent to the gallows," he said.
It was during his final jail stint that Mr Azahari decided to turn his life around, completing his O- and A-level examinations a few years before his release.
"I saw around me older, hardcore prisoners and it made me think: If I keep going down this path, I will come back. The next time I come back, it will be much tougher."
He was released in 2014 and found a retail job through the Singapore Corporation of Rehabilitative Enterprises, where he met his wife.
The couple got married late last year.
Now, Mr Azahari is pursuing a diploma in chemical engineering at a polytechnic.
"Taking drugs, the fun is short-lived," he said. "If you're an addict, most of the time you will think of ways to find money... maybe commit crimes to get money. I don't think it's worth it."
Looking back, he said: "If you spend time in prison, what do you get in life?"