Most of the people answering in this thread have 1000+ blu-ray collections, so you know when they feel a movie's worth owning on blu: in all circumstances.
jk jk
My collection's getting up there though, which is kinda scary. I wish I was more discerning in my purchasing habits. Ideally, every movie in my collection should be special to me in some way.
I actually have a system by which I decide which movies are worth buying. I rate every movie I watch on imdb, and then I keep and maintain a list of every movie I've rated a 9/10 or 10/10, ordered roughly by preference. Then somewhere down the list in the "9s" I have a "cut-off" above which I buy movies, when they're available on blu-ray, and below which I don't.
The problem is I'm buying mostly movies I've already seen, and I mostly watch movies I haven't seen. So when an obscure old movie is announced for blu-ray that I'm interested in, I find a way to see it first (usually in low quality) to know if I want to buy it. So I watch it in low quality, decide I like it, immediately order the blu-ray, and then
don't watch the high quality blu-ray, maybe for years, because I just saw the movie. Which seems counterintuitive. I do blind-buy movies occasionally, but usually only under the rare circumstance that I think the movie is a sure bet.
I also tend to buy movies below my "cut-off" for various reasons: I want to watch the movie again and think I'll like it more on a second viewing, or there are a couple filmmakers I want to own all their movies, or in the case of some obscure Asian stuff available from certain boutique labels, there's stuff I can't help but to buy.
With every purchase, I risk setting a new bad precedent for myself, haha. But then, sometimes I wish I bought less of the standard edition blue amaray mainstream stuff that's readily available at all times on TV, Netflix, and 100 other places, and actually more of the obscure special edition Japanese titles and whatnot that I actually really
like to collect.