The entry level Beatles fan is the kind of person who, having heard and liked some of their music, actually goes out and buys a couple of their albums. He will typically buy Sgt. Pepper’s Lonely Hearts Club Band (it being their most famous), followed perhaps by Revolver or Rubber Soul (having taken note of the popular but debatable belief that those are among their best) and a hits collection. This is not an unreasonable selection as it is highly likely that if you were to ask ten more long-standing fans to pick three essential starter albums, no two would agree. The new fan is just at the beginning of the journey and he is not, as yet, aware that this is merely the start of a very steep, very slippery slope. Sgt. Pepper's Lonely Hearts Club Band (LP, worldwide, 1967)
Having absorbed and grown to like the initial handful of albums and craving for more, our fan moves up to the next level when he decides that he wants to own a complete set of Beatles songs. Before the era of the CD, this was not a completely straightforward task, with songs scattered across a variety of singles and EPs. These days, however, the task of acquiring the tracks released while The Beatles were a functioning band is much simpler so consequently, he buys all twelve original UK albums, plus Magical Mystery Tour and the two Past Masters volumes. Adding to this the post-breakup collections of live and broadcast performances and the three Anthology archive sets, the job is done. Importantly, too, nearly everything needed is available in CD format with only two live albums and The Beatles' Movie Medley only to be found on vinyl. Our happy fan is very pleased with himself and, although he doesn’t think much of Yellow Submarine or You Know My Name (Look Up The Number), these are necessary acquisitions to have the complete set. From now on, things take a decidedly more difficult turn.
By now interested in all things Beatle, our fan’s happiness is short-lived, however, when he discovers that, although he owns all the tracks the group released, there are a large range of compilations, singles and EPs and so on that were originally released but which are missing from his collection. Suddenly, the size of the task has increased enormously. Thus begins the search for a complete set of releases, certainly all the British ones but probably also including the American ones too as they were very different before 1967. Slightly eased by the release of the US Capitol albums on CD, this is nevertheless the first serious delve into a search for vinyl releases that never came out on CD in their original configurations. The hunt is long and exhausting but eventually our fan gets there, the proud owner of a complete set of releases. He is now well on the way to developing a fully-fledged obsession. 
Once again though, this happiness does not last long. Our hapless fan has by now taken to reading extensively about the group. To his dismay, he finds that his collection is very far from complete. For a start there are the mono releases, which often sound significantly different to their stereo counterparts. Then there are alternate takes and mixes that were often put out, usually inadvertently. These variations are, at best, minor and are often very hard to distinguish. Naturally, however, he has to have them, but finds that the search is even harder than before. By this stage, the objects of our fan’s quest are limited pressings, are on now-defunct formats or only came out in far-flung territories. Despite this, though, and even considering that the definition of what is and is not an alternate version is hugely controversial, our fan might eventually be able to achieve this level of completion, perhaps even with his sanity still reasonably intact.
But then one day, a final calamitous realisation dawns. He spots a copy of the Spanish Por Siempre Beatles or the Brazilian Os Reis Do Ié, Ié, Ié!. Not only were there a vast number of albums with different tracklists released all around the world, but even the familiar British titles came with a range of alternate artwork. This time the potential search for completeness is an order of magnitude even harder still and is, realistically, beyond reach. Literally thousands of acquisitions would be required, even if it were possible to create a definitive and accurate list of every different variation ever released. But by this time, our sad victim is unlikely to give up though; he’s been on this quest for too long for that. Only an unfulfilled and bleak future awaits. There will always be that missing Peruvian stereo pressing of Rubber Soul from 1966 or some other such obscurity just tantalisingly out of reach. Thus our fan is ultimately doomed to failure. The final, terrible, realisation dawns. It is not possible to ever own a complete Beatles collection. All you can do is build a level of partial completion.