In short I will say I am pro sampling in general, and I feel MarshalN gave good reasons in this post. I almost feel like I should have a footnote anytime I say I am pro samples. The following exceptions a centered around familiarity of the type of tea in the samples. I mean if you know very little about the tea you are making, it is like driving to somewhere you have never been before in an area with which you are unfamiliar. Basically you have directions or guidelines on how to get to the end result, but you are so focused on the details such as turn left on Vine street, that you tend to overlook the scenery for blocks leading up to Vine street because you are so focused on doing the directions precisely.
If I could stretch my driving metaphor a bit more, it may be that the person who gave you directions is a bit unfamiliar with exactly where you are coming from so it could be that the directions were slightly inefficient, or that you had a way that is much better for you to get to the end result of good tea. Consider the problems with the other route things such as construction or excessive number of traffic lights, which would translate into tea as something like excessive worry over leaf/water ratio, and water temperature. Though I do know some people that like to worry about those details in excess, which brings up a Tea Brewing Art vs. Science discussion, but in reality everyone has to find their own way, and I personally when it comes to tea I like to feel at ease, and in a sense let the moment judge certain steps.
The teas that are the main inspiration for this post are Dao Tea's Balhyochas. Which if you have been following along with some of the discussion associated with the tasting sponsored by Mattcha's blog. It honestly boils down to while trying the two Balhyochas were an eyeopener as a completely different type of tea than I have ever tried. Honestly it is a tea that is somewhat paradoxical the more and more I think about it, it is not quite a black tea, yet not quite an oolong. The most baffling part about this tea is the best sessions of it I have gotten the first infusion is a light amber color much like a mid to light roasted TGY. While that first infusion was good, the best infusions seem to come later where when given hotter water and longer steeps out comes a nice dark ruby color which is absolutely delicious. Though as with most teas the first infusion or two are often the best in a somewhat undebatable sense. So my first inclination was I have been messing up the first infusion or two of this tea, I should try and get the dark ruby color sooner, but as resistant and resilient as these Balhyochas are, if I should try and get more out in the first infusion it is always slightly too strong in certain senses, and then the whole tea fades to quickly.
So while I am in favor of sampling many different teas especially when exploring a category, I have a hard time believing that until you are rather familiar with that category of tea it may be a bit of an effort in futility.