Some toys are able to impress me the first time around, while others need a few more tries. I try to give most toys at least 4 or 5 chances before I decide if it's a dud or not, the exception being if the first try was so incredibly awful that I can't bear to try again (or if the toy manages to break very fast).
More or less. I've had some that I think are ok, and turn out to not work for me, and others that turn out the opposite. It depends on the toy! Most of them are readily apparent whether or not they'll work for me, though.
to know if I'm going to like it, I can tell right away. To figure out all of the ins and outs of the toy? Unique things or things that I don't like quite so much? That takes a few uses and my opinion has never changed.