Very!
I try to purchase only CDs which I am fairly certain I will enjoy for a long time. Sometimes I get fooled by samples or fool myself, and those get tossed, eventually. I periodically prune my collection, keeping the ones which bring great joy and dumping the posers. I never buy or keep a recording because of its popularity or historical significance. I am not a collector, but only keep CDs I know I will continue to listen and enjoy.
Not all releases are great from an artist. Sometimes I only like part of what is on some of an artist's releases. If I like the tracks well enough I will rip/burn those tracks from multiple CDs for my own personal "Best Of". Sometimes it is just a matter of eliminating one or two clinkers in the bunch so I'll do just that - so I never have to hear them again and can enjoy the remaining to their fullest.
Also, there are times I think the track order stinks so will rip/burn for better flow of the tracks.