You should be paying very close to aspects, as they are supposed to be a conversation between the player and the Game Master. It's the player's way of letting the Game Master know what they want to see in the game. If you have aspects related to blasters or rusty X-Wings, then you can expect that they want to experience gunfights and aerial dogfights. If they have an aspect like "Everyone Thinks I'm Han Solo", then you can expect that they want a lot of mistaken identity plots related to their character. If they have an aspect like "Use the Force!" then they obviously want to have a Jedi-related plot attached to their character.
If they don't have any aspects explicitly related to being a droid, even if in the fiction they are a droid, then you can expect that they don't want to deal with discrimination based on their being a droid. They don't want to deal with interactions that are summed up by "We don't serve your kind here" or have to deal with droid liberation rights. Just like if you have a female character with no aspect like "Striving in a Man's World", then they probably don't want to deal with gender-based tropes or plot lines. It's just not part of their character or the story they want to experience.
Hendell:
It is this very versatility that makes Fate difficult for inexperienced gamers to really make use of. Sure they can write a few things down and those may matter from time to time. But the system offers little or now guidance about what helps and what doesn't. It can also be a very quick trap into thinking their characters can simply do anything.
You could make the case that they
can do anything, but it just depends on what they're willing to pay, resources or time. Part of this, I think, is that players aren't willing to concede very often, because it so often feels like losing, and they don't like to lose, even though it's a legitimate part of narratives and the game on the whole. Make sure players understand that conceding is okay and also that they can change the parameters of a conflict in a sort of ongoing negotiation.
It's also imperative that the Game Master meet them halfway. That's the social contract part of the game between player and Game Master. If the Game Master is throwing challenges at the players that don't match any of the players' aspects, then something is going wrong.