Accidental double post of topic so I deleted this one. (not sure how to actually delete it).

I'm not sure there's any intention by the developers; this is akin to people incessantly searching for secret doors in my mind. It's going to work differently at different tables.

On the one hand, this could get annoying, but on the other hand, it lets someone who paid XP for certain skills to succeed. It seems like the best throttle for this is time. If everyone is spending time looking for one item, what else are they missing out on? Surely they're not going to be able to do this to complete everyone's shopping list. Additionally, if an appropriate failure is rolled and the item is restricted, negative attention may be attracted - and all of a sudden, an innocent shopping trip just turned into a blaster fight while fleeing from the authorities. Just because the players are giving you lemons doesn't mean it's going to turn out to be lemonade!

There's always the surefire method of discussing it out of character and out of session - if the group can reach consensus and everyone is having a good time, then is there any harm?

I think the intent was to leave the specifics up to how you want to run your game. However, a few points.

• There is precedent in some of the published adventures for having the character with the highest rank in a skill - stealth, for example - to make the roll for the party. This gives players who invest in skills like negotiation and streetwise or talents like Know a Guy or Black Market Contacts, to have their times to excel, even if that comes more often between scenes.
• Many of the skill checks are one check to determine outcome. You can have the players discuss how they are going about their search, how they are each contributing, and add setbacks or boost dice depending on what's happening. You might give the Face character a setback for not knowing anything about a blaster the merc is looking for. Or, if the merc is with him, describing the item directly to Mr. Fence, that can be a boost instead. But, once the roll is made, that is the outcome, period. You can try again later in a different location or situation, but something has to change in the setting before you do.
• You could allow re-tries if you want to. Perhaps add a purple or black for each re-try.
• Skill checks are skill checks. While this may be taking place between scenes, I still do it in session, after the Destiny pool has been rolled, and I have no problem flipping a point to upgrade the difficulty, especially when they are looking for Restricted items.

There's a lot you can do with how the dice come out to interpret what exactly happens. If the check actually rolled a lot of successes, but they were canceled out by failures, you could say "you've covered every inch of that marketplace and talked to every merchant. Nobody has what you're looking for." Maybe they fail, but have advantage. That could mean they find something similar, or a merchant gives them a referral to someone - in another system - that has what they are looking for.

You can use threat to drain them of money, such as paying docking fees or bribes for information, whether or not it turns up the item. Success with threat can also mean that they find a merchant who has the item and knows that nobody else has it, upgrading the merchant's negotiation.

See the many responses in your follow-up thread: https://community.fantasyflightgames.com/topic/222298-searching-for-gear-as-intended/