It occurs to me, a separate-but-interesting question is, what are recurring cycling costs only, i.e. keep original purchase and sale price out of it. So cost would include wear items like tires tubes patches chains cables housing bar tape etc, but it would be very hard to draw a line between upgrades and regular items.. I.e. when you bought that bike, and new pedals a month later, are they included in the maintenance costs, or do they count as the cost of the original bike because you planned for the bike you bought to have nice pedals, it just took a little while to shop for them?

On the flip-side; for some people upgrade-itis is such a habitual cost it should be considered a recurring expense.