First read this very interesting article by Ganesh Shankar on the same topic.
I thought I will do a quick check on my expenditure pattern. Here are 2 charts.
This first one, as expected, shows that lenses and its accessories account to almost 50% of total expenditure. Another important expense area to me is the one on learning – on books and on workshops. Am happy that I spent 5% on it.
Support – tripod, ballhead, plates
Accessories – bag, batteries, remote, etc
Learning – books, workshops, etc
Lens accessories – filters, adapter rings, teleconverters, etc
The second chart is too short to extrapolate over time.. but is inline with my belief. Equipment expenses are clustered closely together over 2-3 months every year.