First and foremost thing you should know working with an Apartment Locator (Or any other Real Estate Agent) is they don't get paid unless they lease you an Apartment (Or House). That being said, it is only in your best interest to be honest and upfront about your situation. If you are worried about bad credit or criminal history TELL THEM! They will only take you to places that will approve you or won't give you a hard time. If you have a broken lease or eviction (recent or not) TELL THEM! They will help you with strategies on how to get approved like taking you to places that wont confirm rental or that do instant approvals. If you are not 100% accurate with the information you give the locator they may unknowingly take you to places that will deny you. You lose at least $50 every time you get denied and any amount you paid over an application fee will be returned within 30 days! Again, Apartment Locators (Or any other Real Estate Agent) don't get paid unless they lease you a place to live, so the major benefit of using an Apartment Locator (Or Real Estate Agent) is they will take you to places that will approve you and 90% of the time it can all be done in a day!
Its a common misconception that working with multiple Locators (Or Real Estate Agent) is a smart idea, but in reality it is by far one of the biggest time sucks that exists. Not saying you shouldn't fire your agent if they are just absolutely horrible like only showing you places out of your budget or just plain non-responsive. But if you contact multiple Locators and give them the same search criteria for same location and price range, they are likely to come up with the same results. Most likely you wont even meet with every agent you set an appointment with anyway but they have all taken time to do the research and call to get the pricing/availability for you, its even worse if you actually meet with more than one agent because somebody is going to be working for free. If you do find yourself needing to work with multiple agents at the same time let them know prior to touring because it could create an actual Legal/Professional conflict with the agents that you don't want to be in the middle of.
We aren't talking accidentally leaving out a previous address on an application or even necessarily lying. When you are in the process of giving your locator the specs of what you are looking for be sure to give what you can actually pay for rent or what your non-negotiables are. For example.. If in reality you can pay $1300/Month for rent but you tell the locator you max budget is $1200/Month for rent (for whatever reason) OR not telling your locator you have to have 1st floor or Washer/Dryer connections. It creates the illusion that they aren't finding what you are looking for. Its ok to be "Picky" that is what they are there for is to find you an apartment (Or House). Given they aren't apartment fairy's so if your criteria is too unrealistic they will most likely let you know. If you are working with a locator and they are showing you not so good options its either because your budget is not where the market is at in that area OR you are giving (Maybe unintentionally) inaccurate specs to your search.
Be careful with Pricing you see on Apartment search websites and the apartment websites. prices are often misleading and you could miss out on an awesome apartment or special. One of the major benefits of an Apartment Locator is they will actually call the same day to get the accurate pricing, availability and current specials that the Internet doesn't tell you most of the time. Also if you are worried about any qualifying issues a Locator will only take you to places that will approve you. Its hard to find qualifying criteria on any apartments website.
Your Agent or Apartment Locator is just as excited when you get approved and just as bummed if you get denied. Another benefit of using an Apartment Locator is they most likely bring you to a community that will approve you to begin with but worse case scenario they will help you figure out why you were denied so they can take you to a place that will work with that qualifying issue.
Searching for an apartment is not like searching for a house. Pricing, availability, specials, and Look & Lease specials literally change every day for apartments so a list of properties you see today won't have the same price or availability a week later (or even next day) when you want to apply. Best route is to wait until you have the ability to put down an application to lock a place in before touring or contacting any Properties/Locator for availability.