As far as coins and currency go I kind of believe that to be true. Rare cards are a different matter. If it is something that is close to impossible to find then I guess you have to pull the trigger no matter where it is on.
Looking for any Penny Hardaway, Giannis Antetokounmpo, Kawhi Leonard, Kristaps Porzingis, Nicolas Batum, and Frank Thomas stuff I don't have!!!