Some people seem to get away with ignoring the cleanliness issue, and don't have problems with saddle sores. Others have experienced extremely bothersome problems with saddle sores and other saddle-related issues.
Some people seem to find it important to be diligent about cleanliness, while others are more lax about it.
One factor might be individual differences in susceptibility or resistance -- and there are probably other factors involved as well.
What are some of the other factors that contribute to saddle sores and other saddle-contact-area problems?
What are the best ways of preventing or staying free of these sorts of problems (which can be severe, and ruin an otherwise fine trip), especially while on extended tours?