Other than books, I do not consider myself a collector of much anything. I don't seem to get much satisfaction by hoarding material goods. But, there are people who have a very strong desire to keep almost even the most obscure of items for future use, or just for the purpose of reminiscing.
To these "packrats" that do though, I say, thanks! Because of these avid collectors, we have much of the material culture now found in museums, paper items housed in archives, and yes, even books stacked in libraries.
A good example of how the "packrat" assists historians in their work is illustrated by a friend of a friend of mine from East Tennessee. This man, who has lived in his town for many years, was known to be a respectable and honest fellow to many people in his area. Due to being a pillar of the community, he was often called upon to serve as executor in estate settlements, especially those of the elderly who didn't have immediate families. When family papers had no where else to go he rounded them up, attempted to determine their historical significance, and then donated them to historical societies and libraries. Many of these papers dated back to the early 1800s and included such diverse items as personal letters, tax records, store ledgers, and even receipts for slave transfer sales and manumissions. Without the pack rats who held onto these seemingly worthless pieces of paper, much of what is known about the local history of this man's town would have been lost. Once these items end up in an archive or library they are the "stuff" historians use to write history. They are the primary sources that confirm or deny the historian's theories and inferences, and serve as the foundation to their historical works.
Much along the same lines of paper documents, material culture items that are found in museums come from mainly two different sources. First, people who collect items of a specific genre over their lifetime, and then who wish to see them shared and preserved for others to learn from; and second those that inherit or by some other means come to own items they have no interest in possessing or taking care of; either way, if it ends up in a museum, the public are the ones who benefit. It would certainly be a shame for something that is unique or antique and in good condition to find its way to the landfill when instead it could serve to teach children "what we used in the old days," but unfortunately often that is just the case.
I am not a believer in keeping junk, just for the sake of keeping junk, but if you have something that you think might be of interest to a museum or archives, please make the attempt to offer it before throwing it away. If you have papers, letters, or an old diary that you think may be useful to researchers, organize them, take care of them, and make plans to donate them to your local or state historical society or university archives...like me, future historians will thank you.