瑜伽論記 15.275

15.275

言定不定故者，謂有中夭無中夭定壽不定壽也。受非愛非愛，善趣惡趣果也。歲劫數等所安立故者，即約壽量分齊或一劫等也。

Regarding "due to being determinate or indeterminate": this refers to the presence or absence of premature death, and determinate lifespan or indeterminate lifespan. "Experiencing the unpleasant and the pleasant": the fruitions of good destinies and bad destinies. "Because of being established by the number of years, kalpas, and so forth": this is according to the measure of lifespan, or one kalpa, and so forth.