Clipping.

Hello, I am new to blender. It has been fun so far, but I am starting to hit a snag in some of my older training. Originally I was taught that clipping was a very bad thing and I should never do it unless I can’t help it. I have done a few tutorials, some advise against clipping… others are fine with clipping. Do I need to unlearn this old habit or keep it? What is considered good or clean modeling habits?

Thanks.