Strangely enough, I wrote about loss a few weeks ago – and then I lost the file! Truly, I fumbled the 'save' button and it vanished. Very apt.

Although losses occur at every stage in life, they accumulate faster as we get older. A subtle and insidious one is to become invisible. I first noticed this when a cluster of teenage girls would walk towards me in the street as if they could walk right through me. I've taken to holding my ground and even uttering a firm, 'Excuse me! I'm not transparent!' I can view this one with some humour and I understand the need to walk tall and dress more brightly in defiance, but it's a harbinger of other more serious losses.

So many things change over time. We lose our children to their new relationships with partners and spouses, busy lives with their own children, to travel and to settling overseas in ways which gradually become less an OE and more a permanent migration. Or we can grieve their loss and they come back, keeping us on our toes as we get used to their absence and then fit them back into our lives again.

Friends can do this too, ebbing and flowing in our time and space.

For the first half of my life I moved every few years according to job requirements. It was a familiar pattern to me because when I was growing up, my father's work in the public service involved moving from town to town in order to gain promotions. As a child I found it painful letting go of friends and making new ones as I adjusted to very different styles of schooling. When I came to Nelson I was committed to seeing my children through to the end of their schooling and by the time they left for University I found I had put down very deep roots.

However, if I thought that would protect me from losing friends, I was very wrong. Some have moved away, some have died, some are still in the same town but we rarely meet. I don't like losing friends and for a long time I was a great letter writer but that's no longer how we keep in touch. I still send birthday and Christmas cards to people all round the country and in some places overseas, but increasingly it takes thought and planning to maintain the friendships I have and if possible create new ones.

Growing older can also mean losing favourite activities. I remember my father sailing his yacht and riding his motor-bike all through his seventies. As his eightieth birthday loomed he realised both the work of maintaining the boat and the risk of falling from the motorbike increased and, not wanting to be injured, he sold them both. I know this was very sad for him, not only that he lost things he loved but also that giving them up said something about coming to the end of his life.

Inevitably, our parents age and as the roles reverse we lose their support and guidance, becoming the ones to give support. With their deaths we lose the buffer between ourselves and the void, forcing us to face our own mortality. For many, watching friends and family members suffer losses due to dementia can be a slow, sad departure which is drawn out over a number of years and the grief is hard to focus because that person is still there, although greatly changed.

So far, although there are some things I probably won't start – skate-boarding, skiing and if I volunteer for a bungy jump you'll know dementia has set in - the only activity I have given up due to aging is my work. This wasn't an easy decision. My career was a huge part of my identity. It gave me status, mental stimulation and a way to give service in the world. I knew that once I walked away it would be very unlikely that I could return. But I was also aware that I was no longer as sharp as I had been and the stress of other people's trauma and sadness was taking a toll. I haven't regretted the decision but I do feel lessened by it.

Other losses will inevitably creep up on me. In the mean time I aim to keep life as full as I can.