Most of the failed au pair experiences I've witnessed can be traced back to a single root cause: when one (or both) parties did not understand their own needs, and/or choose to ignore them during the au pair/host family search.
Real-life example #1: a young French woman who takes up an au pair placement over the summer to speak French to a little girl, when in reality her desire is to do a full language immersion, and not to have to speak her mother tongue at all while in Spain.
Real-life example #2: a family with three young children, putting out an ad for an au pair to play with their children in English, when what they are really hoping for is someone who will take care of the heavy housework, the ironing and the cooking.
It seems obvious that the two examples above were doomed to failure from the start, but that's also hindsight for you, it's always 20/20.
So why does this happen? In my experience, it is because people know they cannot have everything, and so, during the search for an au pair or a host family they feel they need to start giving up things. The problem is when they give up something that is so important to them, so integral to the success of the relationship, that it never stands a chance.
That is why we encourage clients to write both a wish list and, most importantly, a must list:
Notice the difference between them? Your wish list is like a letter to Santa Claus, write anything you want on it. If you find a host family or au pair who meets all your wish list criteria, that's brilliant, just keep in mind it might never happen again.
If you don't, no worries, you'll have the most important things distilled on your must list as well. These are the ones you really need to focus on, and only give one up if there is a strong, compelling reason to do so.
It is not about being less demanding but, rather, about knowing what matters most to you as a host parent or as an au pair, and being able to zoom in on those most important things, to find a real fit on the other side.
Which is of course the whole point of the exercise.