花无百日红 huā wú bǎi rì hóng
[good times don't last long;A flower,though beautiful,cannot retain its beauty for hundred days] 花不能常开不败。比喻青春易逝,好景不长
人无千日好,花无百日红,早时不算计,过后一场空。——《元曲选·儿女团圆》