Any mother with young children finds it hard to hold down a permanent job.
For Kelly Adie, of Dunedin, the balance is more tricky - she has multiple sclerosis, works as an insurance risk surveyor, and has two primary school-age daughters Olivia (8) and Sienna (5).
She says it's like walking a tight rope - pacing her energy is important.
Few would notice anything unusual about the bubbly 42-year-old, which makes her somewhat self-conscious about using a disabled parking space, or taking more breaks to sit down than other mothers at school events.
''It's like walking on a tightrope. At some point you can fall off, and get back on it again.
''There's no point worrying what might happen.''
When she was diagnosed, soon after giving birth to her second child, she made a choice. As well as a newborn, she had a 3-year-old. Either she could ''sit and get depressed, or suck it up''.
''Life doesn't just stop, and they certainly weren't going to stop.''
She says without the support of husband Bryce, and her parents, Cathrine and Colin Perriman, she could not have achieved what she has in the five years since the diagnosis.
She works three days a week, and says her employer is ''amazing''.
She had been 36 weeks' pregnant when she developed sight problems in her left eye, and was diagnosed with optic neuritis.
She was told it was a possible sign of developing multiple sclerosis. A couple of days after daughter Sienna was born, she started losing sight in the other eye. About two months later, she was officially diagnosed.
Because of confused messages to her brain, her left leg burns all the time. She wears shoes as little as possible, preferring sandals if she must wear anything. Heat worsens her symptoms.
She says she is a glass half-full person, and figures there is always someone worse off.
The first year with it was tough; she was in hospital every couple of months, as the disease kept attacking her eyes. It was unusual for the disease to attack so repetitively, and she says the excellent treatment at Dunedin Hospital saved her sight.
She praises the ''wonderful'' multiple sclerosis nurses at the hospital. She contacts them directly, often bypassing the GP. It means dealing with health workers who know the illness well.
''You don't have to explain your situation to them. They know exactly where you are at.''
Her quality of life is set to improve because Pharmac is funding new drugs, meaning she will no longer need to inject herself every two days.
''Hopefully, by the time you print this'' she will be on tablets, making life much easier.
She hopes for a cure, and figures that moving on to superior medication within five years of receiving her diagnosis shows treatment advances happen.
She had never liked heat, and was never one for sitting in the sun. Now, heat causes symptoms such as fatigue to become severe, and she keeps the curtains shut in her Abbotsford home when it is sunny.
''I'm not looking forward to summer, because summer is tough with MS.
''One of the things I find difficult is when you go to something at school, and the other mums are a lot more active.
''You are sitting back, and you feel they think you are lazy ... I'm just watching out for my health so that I can continue to be with the kids.''
Before she started a family, she had planned to take her children to Disneyland. This became a much more difficult proposition when she got sick.
But with careful planning, the family made the trip successfully, in February 2013.
''As it turned out we didn't need to worry about it, because it went really well.''
Multiple sclerosis
• Autoimmune disorder of the central nervous system including brain, spinal cord and optic nerves.
• Central nervous system is responsible for conscious and unconscious functioning, including movement and response to sensations such as sight.
• The term multiple sclerosis refers to areas of scarring (sclerosis) scattered through the brain and spinal cord.
• Scars result from the healing patches of inflammation that are the cause of damage to nerve fibres.
• Varies widely from person to person. Some experience mild symptoms over a lifetime, while others may rapidly deteriorate to severe disability.
• About one New Zealander in every 1000 has MS. More common in women than men.
• Cause unknown, but is more common further from the equator.
Source: Otago Multiple Sclerosis Society
