The Time of my Life

I don't want to read Catcher in the Rye again - or Salinger's short stories - though I was impressed by them when I was around twenty. Nor am I tempted to reread Wuthering Heights (though Jane Eyre is another matter). I won't be returning to The Hobbit or Lord of the Rings or Mervyn Peake's Gormenghast trilogy, all cult novels when I was a teenager (taking the Peake trilogy down from the shelf I see that they were given to me for my 21st birthday - and I haven't opened it for, ooh, I'd rather not say how many years). Are there novels that it is best to read when you're young as I did with all these? And conversely are there novels that one should keep for middle-age or old age?
The Great Gatsby strikes me as a young person's novel, yet I could happily reread that. And it's the same with To Kill a Mocking Bird. In fact I didn't read that until I was middle-aged and loved it, but I think the optimum age for reading it is probably mid teens. On the other hand Proust is surely a writer for later life. You need to have been through the mill a bit yourself really to appreciate Swann in Love.
There are some writers who have something new to offer as you return to them through life. Tolstoy is one. As a young woman I thrilled to Anna Karenina's tragic love story, but it wasn't until I reread it as a mother that I understood Anna's anguish at being parted from her son. Jane Austen I can always go back to, though it's more often Mansfield Park or Persuasion now, rather than Pride and Prejudice. Dickens was often pushed onto the young reader when I was young, but I think that was a mistake. You should be an adult to read him. Trollope with his generous sympathies and his understanding of human relationships is evergreen. And Middlemarch is the perfect novel for any age. We have chosen that for our book group's annual big read and I am looking forward to.
Are there books that you loved when you were young, but couldn't bear to reread? Is there anything that you are saving for old age?