At first, I tried everything under the sun looking for the "it" juices to keep in my rotation. But now, like you, I'm so happy with my two go-to vendors, that I shy away from ordering new things from different places, b/c I know I could be wasting money on juice that I won't like. Not that I wouldn't try something new, but the urge to keep exploring isn't there anymore.
When I do try new juice, it's from the vendors that I already love and almost always am happy with what I try. I think the trick is...most vendors use a "signature base" liquid, so if you like one of their juices, you'll probably like a lot of what they have to offer, b/c their stuff agrees with your taste buds. Second, ordering from vendors that experienced vapers recommend usually works out well too, that's how I found my go-to's. If you're happy, then I'd say stick w/ what you like until you don't like it anymore...if/when things change, you'll always be able to keep searching later on.