Replay by Ken Grimwood

Jeff groped without success for an explanation, something that would make even the vaguest form of sense.  He'd read a fair amount of science fiction as an adolescent, but his current situation bore no resemblance to any of the time-travel scenarios he'd ever encountered.
--Ken Grimwood, Replay (Harper Collins 1986)

I'm not much of a reader of fantasy but I am interested in time travel.  I recently saw Alfred Werker's film Repeat Performance (see my post of 1/3/20) and was directed, from IMDB, to a review on Noirish, John Grant's blog, where he mentioned Replay, published in 1986, as possibly influenced by Repeat Performance, just as Harold Ramis's film Groundhog Day (1993) was influenced by Grimwood's book.

In Replay Jeff Winston (possibly a reference to Winston Smith, protagonist of Orwell's 1984) "dies" in 1986 and wakes up in his dorm at Emory in 1963, with all his future memories intact.  He starts betting on all the sporting events he remembers from the future and makes a fortune, then dies again.  He gets to relive his life over and over, though re-starting from a later period each time.  He marries in each life, has a child in one life and adopts children in another.  Eventually he meets another "replayer," Pamela Phillips (she had made a movie that convinced Winston she was going through  the same repeating he was) and as they look for other "replayers" they manage to change history by going public with predictions that get the attention of the government.  Jeff keeps trying to make things better but either makes things worse or changes nothing; he keeps Lee Harvey Oswald from killing Kennedy but someone else does it instead.

Grimwood enhances his book with a great deal of loving detail about the news and changing fashions of each relived life, from 1963 to 1986.  Eventually Jeff comes back to his original life and looks forward to new happenings rather than the same old ones.  Grimwood makes little attempt to explain why Jeff and Pamela are replaying their lives and one can only wonder if we all had the opportunity to live again from our schooldays on what would we change and would those changes make any difference.