One person I bought some from described them as being meant to either be collected or read, but not both. RS was and still is made from pulpy paper. Unfortunately they aren't mean to last. Issues from the sixties and seventies tend to be yellow and the paper must be handled carefully as it is very brittle. Like a road map, once they are read, they are almost impossible to fold back nicely - the inner pages stick out and as such, they were exposed more to the elements and became ragged at the edges.
Old Playboys are much better.
Rusty staples and spine stress seem to be a common complaint. I always check two places for books, and you should too - you can pick up bargains and have an idea about what the price range is for a book. They are the ABAA and ABE . Alibris is also good. The ordering systems on these sites have gotten better, and taken the drudgery out of having to contact individual sellers.