What's your depreciation rate?

I WAS at the optician last month, choosing a new pair of glasses to replace the current pair, because my lens coating was coming off in a way that made it impossible to see properly.

After paying for the new pair and going home, I checked my spending records to see how much I paid for the old one.

Then it hit me. I've used that old pair of glasses for four whole years.

That's pretty impressive, I thought to myself.

Then I winced. The new price was some 50 per cent above what I paid for the old. I can only hope this pair lasts five years instead of four.

Analysing consumer purchases

Work with financial statements, and y…