I'm just very curious as I'm passionate about teaching, how do you evaluate 'their level'? I my experience, I can give material that is way out of their comfor

I'm just very curious as I'm passionate about teaching, how do you evaluate 'their level'? I my experience, I can give material that is way out of their comfort zone, but it's my job to make it interesting enough and make enough bridges so that everyone can learn the material well, no matter the starting point. (note: university level, but I also teached numerous times for schools)