Common mistakes made by new owners?

Hello,

I'm new to the community. I'm supporting my daughter to get her first hamster. I'm keen to do things right, learning all the latest advice in hamster needs and care.

I've seen lots of threads with great tips for new owners but I'm wondering what are the most common mistakes that new owners make. I would love to hear the thoughts from the hamster-owning community, please.

TIA