Mr Schwarz usually trawled the internet for inspiration but was also open to suggestions.
The blackboard had become a regular topic of conversation at coffee mornings the couple had with fellow members of the Otumoetai Matua Walking Group.
The quirky, sometimes funny and often thought-provoking messages were changed once a week or fortnightly but more often if inspiration struck, he said.
Mr Schwarz said it had been "rather mind-blowing" how many people had told him and his wife they really enjoyed all the positive messages and sayings on the blackboard.
Mrs Schwarz said quite often the Matua Lifecare van pulled up to take a closer look, and passing vehicles would do another circuit of the street just to read the blackboard.
"We even had one young woman recently give us a box of chocolates saying that one of the messages had really made her day," she said.
"I really get a kick out of doing this. All I want to do is to make people happy and hopefully make them think," Mr Schwarz said.
The keen reader said quite a few years ago he read the international bestseller The Power of Positive Thinking and always tried to think positive thoughts.
"A bit like the Monty Python song Always Look on the Bright Side of Life , he said.
Mr Schwarz's latest blackboard message: "I don't have any bad habits, I'm good at them all," certainly does that.
