I use this all the time

I have a lot of patter that I use in class.  This one is one of my favourites.  I taught it to a class a couple of years ago and a parent told me her daughter lived by the saying.  She had been sat in her car seat struggling to put on her seatbelt, when her mum asked her if she need help the response was "nope, Mrs M says it's okay not to know but it's not okay not to

try!"