I may be a bit of an oddball with regards to this (okay, more than a bit) but I consider an entire cake to be a sample.
For me, a sample just isn't enough to reveal everything about the tea. From which part of the cake did it come? The beautiful, hand assembled exterior, or the nasty underbelly? What is the level of compression? Am I getting a solid chunk of pu or a bag of lawn clippings?
If I enjoy a tea, I need a whole cake of it (at least!). Even if I don't enjoy it, I'd like to be able to revisit it on occasion to see if it has come around, or if my tastes have changed. If I ultimately determine that it's just no good (for me), I can always pass it on to someone who may have a more favorable opinion of it. When I get a tiny bit of something to try, it's depressing to know that it will be gone in another session of two.
Having said that, samples are still a great way to try new items and discover new styles. If my experience with other hobbies is any indication, we tend to go through different phases-
I know nothing, so I've got to try anything, even that $5 cake from the local asian mart sitting next to the basket of dried shrimp.
I want to know everything, so I've got to try everything, including every oddball, no name producer's wares.
I'm a snob, so I've got to have the very best that exists, even if I risk divorce in doing so.
I finally know what I'm doing, so I've got to pare down my selections and concentrate on what I really like.
There's a place for all of these approaches, and more.