With the exception of some knowledgeable record collectors/archivists/mastering engineers in the past (decades ago), I think a lot of the learning about records occurred (at least for me) after the Death of Vinyl.™ The market turned from mass produced, fungible product that was churned out in the millions of copies (remember those days?) to used records, older copies and trying to sort through a lot of information that wasn't generally available to consumers. Thus, differences in pressing plants, decoding deadwax and trying to match up information about specific pressings with sonics, most of which was anecdotal.
In some cases, with popular records, there could be hundreds of different pressings to choose from. People construct general rules about source country- where the record originated from, where it was mastered, etc. but sometimes the "rules" (which are more like guidelines) don't apply in reality (there's the subjective element too). For example, Patto's first album on Vertigo is a UK creation but the US pressing is more bombastic and a fraction of the price (I have both). Sometimes, UK labels like Island used Sterling in NY to master -- so you may hear differences in the vinyl compound or the care with which it is pressed.
For a lot of the "big" classic rock stuff, I accumulated multiple pressings and each one is different- among the better sounding ones, it is just different shadings of the sonic truth. Sometimes, there is a dramatically better sounding one--for example, Jeff Beck's Truth on the UK EMI/Columbia blue black label (first press) sounds remarkably better than any other copy I've heard, including the UK second press and any Epic copy I've had or heard. (I have not heard the MoFi re-do).
Assembling this information requires some research- the Hoffman forum is great for classic rock but you have to find threads where people are comparing pressings and their merits rather than just pronouncing X "sounds great." And their experience, as reported, is like data points that you line up-- if you are looking for bargains where an original pressing is expensive, I've found some old hard rock/psych/prog that is typically tres cher on a UK pressing that is cheaper and pretty close in sound coming out of Australia or NZ- the issue there is simply far fewer copies in circulation from the period.
I don't know anybody that knows it all. There are certain pockets of deep info that get accumulated for specific genres, or labels or bands. Some of the post-bop jazz I like was produced in such small quantities that there are no alternatives except the original small or private label pressing and perhaps a reissue (often of questionable sourcing).
UK Decca were generally superb- from recording to mastering to manufacture. My depth of knowledge in classical is limited though I bought thousands of classical records back in the '80s when they were supposed to be disappearing-- old RCA doggies, the Deccas, Londons, Lyrita, EMI ASD and lots of boutique stuff. Hardly listen to any of that these days, but still have 'em.
It is fun to go down the rabbit hole on this stuff, the chase to acquire can be exciting and if you are lucky and careful, you can land some pretty nice records. I do think the market is inflated right now, grading is not consistent (was it ever?) and some stuff has just gotten astronomical. For that, a good reissue if available, may make sense.
Call me an interested enthusiast with a genuine desire to learn, no guruism on my part- I have several people with whom I share and get info from. And buy from all over the world. DHL Express is a godsend if you have a vendor with an account. Cheap and fast, reliable.
