(idiomatic) to present as new and original things that are well-known or banal; to reinvent the wheel; to put old wine in a new bottle

(idiomatic) to do something useless; to waste time

(idiomatic) to do only what is in one's own interest; to bring grist for the mill; to make capital out of

to throw the baby out with the bathwater / to discard, especially inadvertently, something valuable while in the process of removing or rejecting something unwanted