i guess it depends on how many records i've been buying recently. and i just spent $140 on that mastodon record, i got the 180g MOV reissue of Rain Dogs the other night, and i just pre-ordered "no more shall we part" because i realized i didn't include that in my original giant order of all the other nick cave reissues.
plus, it depends on the artist. there are some artists/bands where i feel compelled to complete a collection of all of their work, and others i don't. the only john carpenter score i own is The Fog, and i don't feel compelled to collect all of the rest of his (despite the fact that i love his work) because it would be insanely expensive at this point.
but with a band like mastodon, i've been working on collecting all of their albums for a while, so getting that 2xLP version of crack the skye was a huge deal for me.
additionally, i justify my vinyl purchases with this: i don't smoke, i don't do drugs, i don't go out for drinks unless it's a really special occasion. literally the ONLY thing on which i spend money, besides food, and gas for my car, and occasional gifts for my wife, is vinyl. and it's an investment. my collection is currently valued at around $18,000 (and that's not even counting some rare stuff i have that has never sold on discogs, so its price isn't calculated) and, though i'd never WANT to sell it, i COULD if i ever had to do so.