Newbie travel trailer buyer question - to slide out or not

hvac wrote:
After all this I stick by my original statement. No slide. Ever.

Not even a little "Sofa" slide? Just kidding. My point is that there are slides that are five feet long and "Super" slides over twenty feet in length. Are they "All" unsafe to use when retracted? How would I, or anyone else, know everything there is to know about every kind of slide?