When your kids are old enough to read and understand simple addition, go over your bank statements with them. Early on they’ll learn that money can make money with interest. Have the compound interest conversation.
You might even consider setting up a matching program for odd jobs– give them a dollar for every dollar they earned on doing small jobs for friends and neighbors, but only if that money is going right into savings. That’s a great way to help them watch their money grow now, and they’ll be more likely to think about that valuable “employer match” when they finally enter the working force and establish that first 401(k).