The Chocolate Cat Caper question

In the past when I collect series when a new book comes out I would go back and read from the first book in the series up to the new one. Now that I am older (much older) time feels crunched and I am trying to read the new/latest book without going back to the beginning. How do you read a new book in series you collect? Do you go back to the beginning or always and forever just read the new release alone? Do you keep all the books in the series even if you don't reread them each time?