This article suggests that the average Briton spends more than three and half years of their lives suffering from colds and flu. That amounts to an average of three colds a year and around three weeks a year off sick. Over the course of an average adult lifetime this amounts to an surprising three years, five months and 15 days suffering from a cold or flu. I guess I must be one of the lucky ones, I can't remember the last time I got sick.