This perfectly formed malaphor is a mashup of “turning over a new leaf” (to change one’s behavior, usually in a positive way) and “a new lease on life” (a new chance for happiness, usually after a hardship). “New” is common to both idioms, and the words “lease” and “leaf” are similar sounding. Both I think contributed to the mental mix up. A big thanks to Martin Pietrucha for sharing this one with the malaphor world.
If you liked this malaphor you’ll love my book on the subject, “He Smokes Like a Fish and other Malaphors”, available on Amazon for a cheap $6.99. A must for every bathroom library.