My unwritten rule for myself is that the parents must work with me to solve any problem that arises and if I can see that they are working with me I'll keep trying until I reach my limit. I hate to terminate families because that means interviewing and transitioning a newbie again which are my least favourite things. However, when we reach our limit we know it and it's so important to be happy and as stress free as possible because we have a really hard job to do every day and we work looooooong hours.