Our daughter was a nightmare with this last summer - we really persevered with putting it back on her (hundreds of times some days it felt like!) and eventually she has learnt that she needs to wear it to go outside in the sun. She does still throw it off but only every so often now. We made sure we wore hats too and made a really big thing of it. Also it seemed to help when we took her out in the pushchair and there were lots of other babies and toddlers in pushchairs with their sun hats on, which we kept on pointing out to her.