This is going to be a long and somewhat detailed post, so I'll put a summary here: vinyl is believed to degrade over a period of decades/centuries, even when not played, according to well known chemistry reactions. Why don't people worry about this? From "The Care and Handling of Recorded Sound Materials" by Gilles St-Laurent, Music Division, National Library Of Canada: Thus far, vinyl has proven to be the most stable of the materials that have been used in the manufacture of sound recordings. However, although stable, its life is not indefinite. Pickett and Lemcoe, in Preservation and Storage of Sound Recordings, states that "failure by chemical degradation of a vinyl disc in ordinary library environments should not occur in less than a century"... Polyvinyl chloride degrades chemically when exposed to ultraviolet light or to heat. Phonograph discs are exposed to high temperatures during moulding and pressing. Unless stopped, this heat would be a catalyst for ongoing dehydrochlorination, which is the release of hydrochloric acid (HCl) from the PVC as a result of thermo-degradation. Stabilization is therefore achieved by adding a chemical to the resin during manufacture. This does not prevent the degradation but controls it, mainly by consuming the free HCl. Sufficient effective stabilizer remains in a plastic phonograph disc to protect it for several decades after pressing. This link gives a good overview of the primary mode of thermal degredation through HCl, zip dehydrochlorination. In the of heat, any free hydrogen chloride in the vinyl solid helps break off more HCl from the vinyl monomer. This HCl also aids in several other modes of degredation; look at the page (and the pages it links to) for more details. The heating of the vinyl during pressing is enough to kickstart the degredation. So stabilizers are added to grab any free HCl, be substituted into the vinyl monomer when any HCL does break off, etc. But clearly, there can't be enough stabilizer in vinyl to capture all of the HCl. Eventually, the stabilizer runs out, and the vinyl will start to decompose. It appears that when this occurs for other PVC applications (roofing/etc) this results in a considerable amount of discoloration and changes in mechanical structure (link). Here's another quote from The Care of Grooved Recordings: The consequence of thermal cycling is that each cycle of temperature change results in a small, irreversible deformation. These deformations are cumulative.... Store discs at a stable, maintained temperature of between 15EC and 20EC. The fluctuation of temperature should not slowly vary more 2EC in a 24 hour period. The relative humidity should be maintained at between 30% and 40% with a slow fluctuation of no more than 5% in a 24 hour period. In other words, the best place to store your records is in a wine cellar. The link does not give any more detail on what exactly occurs with thermal cycling, but I can only assume it's a different process from dehydrochlorination. Perhaps the thermal coefficients for PVC and the other additives are different, and the different rates of expansion introduce pops/ticks into the recording. I dunno. For me, this means several things: Lack of temperature control may be a cause of degraded vinyl quality. Perhaps this could be responsible for ticks and pops in otherwise good-looking vinyl, if it has been, say, left in a garage for a few years. If anybody has access to a thermal cycling apparatus, this could be pretty easy to test, actually - run an accelerated heating/cooling test on a record, do before/after needle drops, and listen for differences. Keeping records in my house isn't fully adequate, because I turn the thermostat 5-10 degrees up during the day, and even if I didn't, I have poor temp control where the records are stored (2nd floor of a house). Even at the optimal temperature, vinyl simply isn't inert, due to the stabilizer eventually running out. Therefore it cannot be an investment that is guaranteed to last beyond only a few generations. It's worth noting that I'm not aware of any concrete descriptions of audible effects of thermal degredation. Nevertheless, it's something that we know exists, so we should be watching out for it. I already know that there are plenty of cases of people playing back 1950s-era LPs that sound dead quiet; I'm not interested in that. What I want to know is: how long records are expected to last nowadays? And how do we know this? are we not paying enough attention to how we store our vinyl?