If you see any of these, rips, tears, folding and creasing, look for another book. The inside pages have medium to extremely severe brittleness. It is a pretty beat up piece of newsprint. It's important to remember that the condition is just one contributing factor. You will be less inclined to part with a rare book easily, and rarity increases value.
Singularity is whether the seller has more than one copy.
If it's your only copy of a particular comic, you might be less inclined to part with it easily. Contribution addresses how the comic fits into a collection. A book that is part of a run of comics makes a bigger contribution to the whole collection. Sentiment is that intangible quality that links you to your books, and comes from love of the artform. Sentiment is never an issue for comic speculators, only for collectors, or for people who have inherited comics from a loved one.