I just recently started putting an expiry date on them. I date them for the end of the year and do any changes over Christmas break if need be.

I haven't had anything too major that couldn't wait until the end of the year. If I did though, I would probably just get them to sign a piece of paper with the new policy.

Actually, I did change my end time from 530 to 5 to now 445 but just told the parents verbally that were in care at the time. It ended up being my late children that kept leaving so I just shortened my day as they left and signed new families on with the new time. Thankfully no one threw a fit over it and now all contracts have 445pm on them