Mild sunburn usually lasts 3-5 days. Moderate or severe sunburn usually lasts at least several days longer. The effects of each episode of this radiation damage, however, are long lasting. Each sunburn increases the risk of early wrinkles, premature aging, senile skin lesions, and skin cancers.
How old does a song have to be to be considered a classic? In my opinion a new generation have to grow to adulthood for a song be regarded as a classic therefore somewhere between 20-25 years would di it.
So, Classical Period music was indeed popular music during the Classical Period, between the early 1700's and the early 1800's. But classical music is wildly popular even today, and it is not likely that the classical craze will end any time soon. See links for more.