IEdit is kinda like real time search and replace. It’s similar to that one vim feature that I see people using from time to time. After a word is selected by the region, you can go into iedit-mode with M-i and while editing the marked region, all other occurrences will be changed accordingly.
(require 'iedit)
(define-key my-keys-mode-map (kbd "M-i") 'iedit-mode)