Depends on if you count shift. I C-M-% (query-regexp-replace) fairly regularly, and that's 4.
(use-package visual-regexp
:defer t
:bind (("C-c r" . vr/replace)
("C-c q" . vr/query-replace)
("C-r" . vr/isearch-backward)
("C-s" . vr/isearch-forward)))
(use-package visual-regexp-steroids
:defer t)