One often sees discussions concerning repairs on lower priced stamps. While collectors do need to be careful about repairs and alterations it is important to remember that stamps are repaired for a reason and that reason is so they can be sold as non damaged items at higher prices than they would be otherwise. Thus repairing a stamp is an economic act, not someone engaging in an esoteric activity. I say this so that you'll keep in mind the two questions that reasonable philatelists ask when they are examining an item for repairs; Why, and when? If a stamp has been in a collection for thirty years and was thought to be a cheap stamp thirty years ago why would anybody waste their time repairing or reperfing it. And when would they have done it? Keep in mind that perforating pins on early Nineteenth Century stamps were not perfectly placed and even when they were, they could move over the course of thousands of cuts into stamp sheets. So perforations are not always exact on these early stamps and just because one perf is a fraction off doesn't mean that the stamp is reperfed. Some philatelists are not satisfied in their examination until they have found a fault or a repair on a stamp. However, if they asked themselves the question of whether it makes any sense that someone would play around with a stamp that wouldn't even qualify for sale on its own, they might be a lot happier in their collecting. Even a repairer's time has value and they are not apt to waste it.
Why and When