But when something out of the blue happens, we're given a sudden jolt, as if to remind us just what a major part of our life that friend is.
And so it was that recently I received a phone call from a friend whose dog I've looked after many times. She'd been unwell so the owner took her to the vets, hoping that a quick check up and some medication would sort things out.
But hearing how she'd been behaving, the vet carried out a number of tests including scans and that's when the cause of the problem was revealed - a brain tumour.
This very sad news upset me. I've known this 6yr old dog since she was a pup. What could I say to a person whose pet has been diagnosed with a terminal illness and whose life span is now weeks rather than years ?
Since the phone call I've visited the owners and their dog. She greeted me in her usual enthusiastic manner and displayed none of the symptoms associated with her condition.
However, I don't think I'll visit her again. I believe the memories I have should be of a dog who was healthy for six years, rather than sick for a few weeks.