MOST of us occasionally double back to the house to check we've locked the front door.
But when Paris Shacklock started doing it at least three times every morning, he sensed something was wrong.
Mr Shacklock, of Devonport, said he had been living with obsessive compulsive disorder for three years, and was starting to get it under control with the help of a good doctor.
According to Reach Out Australia, OCD is an anxiety disorder characterised by recurring unwanted thoughts, obsessions, and compulsive behaviours.
For Mr Shacklock, this meant he needed to check things repeatedly - such as locked doors, taps, the mailbox, product descriptions in supermarkets and electrical appliances.
"On a bad day for an average person with this condition, they would probably check the house door about 10 to 12 times before they're happy with it," he said.
Mr Shacklock said he knew his compulsions weren't rational, but they were difficult to resist.
He said his family, friends, church and neighbours had been very supportive - often helping him check things - but he did experience stigma because of his mental illness.
"Basically, the worse thing about OCD, and other illnesses like bipolar and schizophrenia is people's ignorance," Mr Shacklock said.
"They don't understand what they're dealing with, and it's human nature to get a little bit frightened or scared by something you don't understand.
"But there's nothing to be scared of.
"I was just doing simple little checking things that we all do on an everyday basis, but with OCD it takes a little bit more time."
Mr Shacklock said he hoped his story would raise awareness of the condition, and give hope to fellow sufferers.
"To others with OCD I'd say this: it's alright, keep persevering with your doctor, there is a solution," he said.
"Just be patient to yourself, be kind to yourself, just because you've got this condition doesn't stop you being what you are inside, what's in your heart and in your soul."