"I can't tell you how many families I've looked after over the years."

Carol Keates has been giving up her time at Mater's Parent Aide Unit for 40 years and has loved every second.

She has helped countless people who've experienced difficulty with parenting and needed some extra support, visiting them in their homes and in hospital.

"I started volunteering as a parent aide at Mater in 1979. I saw an ad in the Brisbane Telegraph, did a parent aide training course and just went from there," she said.

"A lot of these kids don't have grandparents so I was a grandparent to them. They just needed some guidance."

Carol said most families she's helped have came from disadvantaged backgrounds, including those from war-torn countries and affected by drugs and alcohol.

"I did a lot of child protection work. But I really liked seeing these families get better and better and even if I could help just two people along the way I was happy with that," she said.

"I love kids and also the challenge to help them and give their family a better life."

Carol, who is a mother, grandmother and great grandmother herself, said it was time for her to move on and focus on her other volunteering work through St Vincent de Paul.

"I have decided to retire because I have arthritis in my hands and legs and I can't get up and down out of chairs and steps etc," she said.

"I can't believe that I am in my 80s now and I started volunteering (at Mater) in my 40s!

"I would definitely recommend volunteering. You come home and think about it and realise 'I did make a little bit of difference today' and I think that is just wonderful."