Ultraviolet (UV) reduction campaigns since 1986 were based on the estimation that individuals get 80% of their cumulative lifetime UV dose by the age of 18. To investigate if this estimation is true, we compared annual UV doses received during life in 164 Danish volunteers: children, teenagers, indoor workers, and golfers (age range 4-67 y) who recorded sun exposure behavior in diaries and carried personal UV dosimeters, measuring time-stamped UV doses. The annual UV dose did not significantly correlate with age but the variation in annual UV dose was high (median 166 SED (standard erythema dose), 95% range: 37-551 SED). The annual UV dose did correlate with days with risk behavior (sunbathing/exposing upper body) (r=0.51, p<0.001) and in adults also with hours performing outdoor sports (r=0.39, p<0.001), gardening, and sun-bed sessions (r=0.26, p=0.02). Teenagers had significantly more days with risk behavior than adults (21 vs 13 d, p=0.006) but not than children (15 d). No differences in UV dose among the age groups were found on workdays. Only 25% of the lifetime UV dose was received before the age of 20 and the annual UV dose was thus independent of age. Reduction of cumulative lifetime UV dose could be obtained by minimizing risk behavior.