by Christopher Brown e , exclusively for Property Secrets

It's that time of year again. Whenever pictures of snow-covered sleighs and Father Christmas making aerial descents on starlit nights appear in the shop windows, a small shiver runs down my spine. It's partly the thought of those cold winter nights. It's also because I know October is letting month.

For some reason most of my tenancies begin and end in the autumn. I don't know if it's the seasonal switch from summer to winter or the prospect of all that Christmas spending that makes Londoners want to move - and hopefully rent an apartment in Browne Towers - in September or October.

Student lets follow the same pattern, as I know from my little nest of studios in Nottingham. Almost every university or college student rents through his academic year from September to July.

October, for me, means shorter days and bigger decisions. Each time I renew a 12-month agreement (most of my tenants are on one-year renewable contracts), I must decide whether to put up the rent or not - and if so by how much.