Good Idea: Putting your keys in your purse as soon as you get home, so you don't have to look for them when you're ready to leave the next time.
Bad Idea: Putting your keys in your purse right away, then forgetting you did that, and panicking while you search the entire house for them and have no idea how you lost them. Then give up, because you're already late for work, and take your husband's keys. Finally, when you're leaving work to come home, find your keys safe and sound in your purse after all, and feel excruciatingly dumb. Especially because you've had some pretty embarrassing key-losing experiences in the past.