How do you know if you need to seek permission to use something (i.e. a copyrighted image or slogan)

Here is a list of reasons why you would need to seek permission from the original owner:

If you intend to use the material for commercial purposes, you must seek permission from the original owner if that material is copyrighted or is a registered trademark

Or if you want to use the material repeatedly- for example if you are writing a book and you want to include a specific image several times, once again you need to seek the permission to use it from it's original owner