So speaks the wisdom of Salvation Army Bowral Family Store manager Colin Pullan, drawn from the scriptures, and so applicable to opportunity shops.

The Southern Highlands has an op shop trail, the paths of which leads from the garages, attics and spare rooms of donors - and the hearts of volunteers.

The charities in turn offer material, financial and emotional support to people.

Acting national manager of recycling for The Smith Family, Peter Lombardo, said their proceeds helped support learning and mentoring programs for disadvantaged children and young people.

Lifeline Macarthur retail operations manager Sandra Cartwright said all funds raised through their shops provided "free crisis support services to help the communities in which we operate."

"The week before spring is a timely reminder for people to clear out their wardrobes and donate items," Ms Cartwright said.

Fr Chris Riley's Youth Off The Streets is a non-denominational charity that helps young people who are homeless, drug dependent or suffering abuse.

"A purchase means you've helped disadvantaged people to improve their lives," said president of its Southern Highlands branch, Kerrin McInerney.

"New volunteers are always welcome," she said. "The rewards are many. Volunteers connect with other people and make a difference to many lives."

The Salvos' Colin Pullan agrees: "It is amazing, the people who volunteer here. It's a very Australian thing, to look after a mate. I can't thank them enough."

For volunteers at St Andrew's Presbyterian "pop-up" op shop in Bendooley St, Bowral, open the first Friday and Saturday monthly, it is about friendship.

The shop has helped bond friendships between the volunteers, but also with its "regulars" who bargain-hunt each month, said coordinator Sandra Boggs.

From fashions and footwear to toys and taxidermy (truly), the local op shops have seen it all. Sadly, not all of it is useable, much less publicly saleable.

"Somebody donated all their grass clippings once!" said Moss Vale's Southlands Care manager Heather Wells, albeit with a rueful laugh.

"We have our 'seasons' of dumping" - the spring-clean of September is such a time - "and it does cost us to dispose of dirty and broken rubbish at the tip."

Southlands Care specialises in food parcels for people and their pets: "They don't even have to give us a name or a reason, it's just what we do."

St Vincent de Paul Society area manager Glenn Bailey said the sales from his group of shops helped fund essentials for the needy, such as food, clothing, furniture, bedding, housing, and financial assistance with practical utilities.

"But we also have to sort a lot of rubbish to send to recycling," Mr Bailey said.

But on balance, the donations are well intended and good for a second life.

Southern Highlands Community Hospice furniture shops manager Bruce Robertson said knowing a donation helped the Highlands appealed to many.

"And a lot of people say, well, you never know when I might need your help."

August 23 to 30 is National Op Shop Week: why not "op till you drop"?