If using the same brass everytime in the same rifle, I avoid FL sizing more than once, and only neck size each time. As mentioned above, overworking brass (the result of constant FL sizing, among other bad practices) will cause something known as "work hardening", which means that each time you FL size, the brass will flow back to the size it was before you FL sized it (the dimensions of that particular rifle chamber) then you cut more, and it will fill the gap again and so on. Brass on the move like this becomes very brittle and will split.