The correctional system's focus has changed over the past 25 years, Mobilong Prison's capacity has more than doubled, and its inmates come and go more frequently than ever.
But Bernie Gelston - recipient of an Australian Corrections Medal on January 26 - has been a constant throughout it all.
These days Mr Gelston is one of the prison's accommodation managers, responsible for 70 staff and 250 prisoners at Mobilong.
The son of a long-serving prison officer, he has spent 38 years in the system after a nine-year stint in the Royal Australian Navy.
His corrections career started at the one place he had sworn he would never again visit - Cadell - but his second home since 1995 has been Mobilong, a "fantastic" prison with low rates of violence against staff.
One of the keys to his long career, he suggested, had been realising that his attitude, not the tasks he did, would have the biggest impact on people's lives.
"We get an opportunity here to present as role models to prisoners we're dealing with and to make a positive change in people," he said.
"We're not going to change the world, we're not going to fix all the world's problems, but sometimes you do impact on a prisoner's life and where he's going.
"I know because they'll come up to you in the street (later in life) and say hello."
Rehabilitation was possible, he said, especially for participants in the prison's group programs; but it had to come from within, not without.
That had remained true as the Department of Corrections shifted its primary focus over the past 25 years, he said, from treating prisoners as victims of circumstance to forcing them to take responsibility for their actions, putting community safety first.
That change was why, for example, ex-prisoners were transported back to Adelaide on their release instead of just being let out into Murray Bridge.
But rehabilitation was easier for some than others.
Plenty of the so-called "first offenders" who arrived at Mobilong as 18-year-olds, whether on remand or for a long-term stay, were already hardened criminals, he said.
Some were the grandsons of the prisoners he had dealt with early in his career.
About 20 per cent of the inmates at Mobilong caused most of the trouble, he said; the other 80pc were simply serving their time.
In that respect, it was important not to judge anyone by his past.
"Every individual must be treated as an individual," he said.
"Take them as they present, not their past deeds and attitudes."
Mr Gelston said he was honoured to have been awarded the Corrections Medal, which he will receive at a forthcoming ceremony at Government House.