Three times a week Derek Benson volunteers four hours of his day at the City Mission in Youngtown, just outside of Launceston.

Originally from Yorkshire in England, Mr Benson also happens to be 90 years old — not that it seems to bother him.

"Apart from my eyes and the fact that I'm a bit deaf, last time I was checked, the doctor said, 'we look to be receiving results back from a 50 year old rather than a 90 year old'," Mr Benson said.

Starting at 10am, Mr Benson sorts through a large cage full of donated books, but the volunteering has become more than just filing in the time.

"When you're 90, you look around and you've lost all your good friends, they've all passed on and you're on your own," Mr Benson said.

"That [the volunteering] breaks my day up and it gives me an opportunity to meet different people here, and also do my job and feel that you're doing something useful from all the donations that come in."

Mr Benson said he could not just sit around and 'twiddle my thumbs' which is when he started at the charity store. ( ABC Northern Tasmania: Fred Hooper )

'He's part of our family'

Operations manager with the City Mission in Launceston, Greg Howe, has seen a big change in Mr Benson since he started seven years ago.

Greg Howe from the Launceston City Mission said that Derek Benson has become like a part of the family, ( ABC Northern Tasmania: Fred Hooper )

"It is his social interaction, he comes here three days a week and we just love him," Mr Howe said.

"He's just a part of our fabric and that's what people become — they become a part of our family and a part of our fabric."

Mr Benson volunteered for Meals on Wheels for 15 years before his wife died and this prompted him to look at other volunteering options.

"That's when I thought, 'Well I can't just sit and twiddle my thumbs,'" Mr Benson said.

Even though he can not see very well, Mr Benson still manages to sort books for the charity. ( ABC Northern Tasmania: Fred Hooper )

'I'm blind, what can I do?'

Mr Howe recalled the initial contact with Mr Benson.

"I remember it very clearly, he said 'what could a blind old man possibly do?'," Mr Howe said.

Mr Benson was upfront about his age.

"I said 'look, I'm 83-years-old, have you any use for an 83-year-old?' He said, 'of course we have'," Mr Benson said.

Seven years later and Mr Benson is still volunteering his time at the City Mission and what he considered the most unlikely spot.

"I said 'in the book department? I'm blind and can't read or write, what can I do in the book department?'" Mr Benson said.

For now at least it seems Mr Benson will be sticking to his routine and his volunteer work with the City Mission which he seems to love.

"I'll keep going for as long as I can stand up and do it," Mr Benson said.