If I have dies I like such as Forster and Redding I just get the collet. But if I have other brands of dies I get the set as the Lee bullet seater is good for low run out and will sometimes be more accurate than standard dies. If you want to adopt the collet die changing spacers can make it work on a variety of cases of the same caliber. You can buy these separately very inexpensively or make your own if you have a lathe.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli