I buy them if there's a "theme" to them.
Example: I have a Rashid; that Egyptian 7,62x39 rifle is derived from the Ljungman, so I also NEED a nice Ljungman and a Hakim, which is the Egyptian 8mm Mauser offspring of the Ljungman and the Rashid's bigger brother.
Then, because I have a Rashid, I ought to also have at least one each of all the representants of that family of semi-auto only carbines in that caliber, let's say a Czech VZ-52/57, a Russian SKS, a Yugo M-59, a Chinese SKS (if a Sino-soviet, the better), an Albanian for the odd one, maybe.
Now, since I already have a Swede M-38 to go along with the Ljungman, I guess it'll be appropriate to also have a nice sample of a Swedish M-96, no?
I think you got the picture...
As for Mosins, since they are like snowflakes (there's not two alike, they say), I made myself a promise: only Finn ones! Not even a Polish M-44, lest I'm doomed to total financial bankrupcy in a few years from now!
A good thing I heard, though: it seems Mosins tend to multiply like rabbits if left alone in a quiet place...
PP.