Apps or other wearable devices can track the number of steps we take, how long we sleep and whether we've burnt off that mince pie.

Leon Wurfel collects data on his sleeping patterns using a special headband. He then compares this , along with other information he has collected on his stress levels to assess whether his diet or relaxation exercises are affecting sleep quality.

''Having the tools available to measure health is very attractive, and I've always loved having a tinker around with these things,'' said Mr Wurfel, a sustainability engineer.

He is one of the organisers of a group in Sydney dedicated to the concept of the Quantified Self, which aims to foster self-knowledge through self-tracking.

The idea originated in the US, and Quantified Self groups have since formed around the world.

''Basically, it's a bunch of geeks who get together to optimise their physical and mental performance, and share what information or gadgetry they've come across,'' said the Sydney chapter's co-organiser, Laurence Wolf.

Monash University medicine lecturer Juanita Fernando said self-monitoring tools were a great way of keeping records, but people should consult their doctor if they seriously wanted to change their habits.

''There is a danger people think they're taking care of themselves, and that they are following the best advice by using these applications. There is an assumption the designer of the app has some critical knowledge, but often that is not the case.''

SECONDS before Hannah Miller allows her one-month-old baby, Imogen, to breastfeed, she taps the timer button on the Nursing Master app on her iPhone.

When Imogen finishes, a record is made of the duration of her feed, on which side, and for how long. Months of data can be turned into spreadsheets and graphed.

“I use it as a reference when I speak to the [National Breastfeeding] helpline to say, ‘This is how I’m feeding, can you give me advice,’” said Ms Miller, 29, from Panania.

A growing number of apps are appearing on the market, allowing mothers to log anything from nappy changes to sleeping patterns.

Ms Miller said after  feeding problems with her first child Jack, now 5, the app helped her achieve a more positive experience for her second child Vanessa, 2, and Imogen. But she believes smartphones cannot compete with face-to-face help.

with Esther Han