Bad Objects - Good Practices

I know that we all struggle with Bad Objects, and there have been plenty of topics related. However, many address particular issue and how to fix it. Wouldn’t it be nice to focus on preventing at the first place?

I would like to invite you to co-create a list/handbook of Good Practices for Bad Objects : -)

I would start with tolerances, which have been explained well in this great post by @ David Cockey

What else comes to your mind?