Don’t throw the baby out with the bathwater.
What it means: Don’t get rid of your valuables along with the unnecessary things.
Origin: This one is nasty, fair warning. In the 1500’s, people would bathe once a year, and they wouldn’t change the water between people. The adult males would go first, then the females, then the children. By the time it was the kids turn, the water would be murky. So murky in fact, that the mothers had to take extra care to be sure that they didn’t throw the baby out when they were dumping the water. That would be extremely upsetting.