Fast travel is a must for me. Some people say fast traveling breaks their immersion, but fast travelling doesn't nearly break my immersion as much as dying does. If I were to attempt to play a character with a no fast travel rule, I would quickly get impatient, especially if my objective was on the other side of Skyrim or in the middle of Bumfuck Egypt. Some people might also say that you're missing out on discovering locations by fast traveling, but if I want to explore, I just fast travel somewhere and then run towards undiscovered locations.