probably 60-ish or more of my collection (which is rather large) are blind buys. i've learned some lessons. i still blind buy a lot, but i'm a bit more hesitant now. i think part of blind buying successfully is really understanding your taste. part of that is just watching a lot of movies.
so for movies i haven't seen, i don't typically stream them, but sometimes i do. let's use 2 recent examples. i recently blind bought Secret Sunshine and Dragon Inn, but other films I really want to watch (and might buy) that I intend to stream first are Under the Silver Lake and Moonlight. so what's the difference? well, with the movies i'm going to stream, neither director has been personally vetted by me. i've never seen a film in their filmography, they're contemporary which means less time tested, and there's not much potential historical or academic value that i can confirm i'm going to get. i might enjoy those 2 films more than the films i blind bought, but they're riskier. now let's look at the 2 films i blind bought. Taiwanese New Wave and the Second Wave are 2 of my favorite moments in cinematic history. King Hu, director of Dragon Inn, is arguably the most important, influential Taiwanese figure predating these 2 movements and this film is a critical component of the history of those 2 waves. It's also considered a wuxia classic (a genre that I love), and it's prominently featured in a film that I love, Goodbye, Dragon Inn. i really want to personally experience the film that tsai ming liang thought was important enough to act as the backdrop of arguably his great masterpiece. even if i don't love the movie, i know for a fact that i will gain value from it from an educational perspective. Secret Sunshine is directed by Lee Chang Dong, who is a director i trust off the back of the only film of his i've seen, Burning. it's, by my estimation, a modern masterpiece that absolutely absorbed me. i watched it twice in like a week, which i seldom do, and so i intend to watch his filmography. owning Secret Sunshine cost about the price of admission, i support the artist in whatever way i can, and if it shows his prowess as a director as well as Burning, i now own it forever. it's a no brainer.
i do not always go for the 4K, but i probably go for the 4K like 80% of the time or more if it's an option. it does depend on the value and the sort of film. and i probably do not fit in in the sense that i don't believe that higher fidelity always = a better experience. i recently got the SLC Punk 4K and love it, i don't intend to sell or get rid of it anytime soon. however, that film really kind of felt at home in standard definition for me. in its low budget, punky grittiness, it kind of just fits. so i've actually considered since rewatching in 4K buying another copy on shitty DVD, as i kind of like that experience for that particular film. but Lawrence of Arabia or 2001: A Space Odyssey are visual masterpieces, if 4K is an option, i wouldn't really consider anything less.
i never go for the blu ray initially and upgrade intentionally. i did it one time and regretted it. i only do it if 4Ks are unavailable and then become available after i already own the bluray. to me it's a waste of money, why buy it twice if i could buy it once? if i choose to go bluray over 4K, it's probably because i don't value the extra fidelity more than the money i'd be saving