Changing the habit of the lifetime. I’ve had the same set of quilting rulers for over 20 years – when I bought them it was difficult to get metric ones . In that time they have got very battered, and my cutting mat, though younger (already replaced once), is equally battered. I don’t quilt any more but I use the rulers and mat for cutting embroidery fabric and paper for book making. I realised that if I replaced the rulers with metric ones, I could turn the mat over to use the metric side – and move away from a measuring system I don’t use for anything else.