Years ago, I worked at a marketing agency, like many post-grads looking to get a foot in the door and some experience under their belt. There are a few things that I learned from my time working on the inside that have stuck with me now that I'm on the outside. 

Any time I hear someone say they're looking to hire a marketing agency, a number of red flags that often go unnoticed spring to mind, along with five questions that you must ask before hiring a marketing agency. Because what every successful startup knows about marketing is that you need to find people who will love your product or service, rendering marketing something of a necessary evil. 

With so many marketing agencies vying for your attention, and given that its an industry with notoriously high rates of deception, it can feel reminiscent of dealing with used auto dealerships. But unlike, say, those car dealers, marketing agencies are--or at least should be--masters of marketing. And so it's not uncommon to get taken for a ride. Because the problem is, that many are really very good only at marketing one thing: themselves.  

By asking these questions, you can quickly weed through agencies and find the best in the business--those with transparency, expertise, and integrity. They enable you to easily tell the good from the bad--so much so, I've been hung up on for asking some of these questions. Talk about the trash taking itself out. 

1. Who is responsible for making changes to my account? 

You've probably been told that you'll get an account manager, but beware: This doesn't mean that the account manager is actually the person who will go in and make changes in your account. In fact, odds are, they probably won't. What they will do is relay your notes to someone else, whose title is likely something  closer to PCC specialist or strategist. 

While this isn't necessarily a bad thing, you should know who will have your password. And you should know that it may make it more of a challenge to get your thoughts across when they have to then be relayed to someone else. 

2. What is your (employee) turnover rate? 

Marketing and ad agencies have notoriously high employee turnover rates, with an average turnover of 30 percent--that's three times the standard business target of 10 percent. In reality, the figure might actually be much higher because agencies commonly use independent contractors, making their employee turnover rates deceptive and appear much lower than they may actually be. 

And while it may not sound like any of your business, it will affect your business if you become a client. In fact, high employee turnover is one of the most frustrating things about working with a marketing agency. After all, every new employee means another time you have to introduce your business, explain your goals, and build yet another relationship. 

3. How many clients are each account manager assigned to? 

Agencies vary greatly when it comes to how many clients each account manager is responsible for. In general, an account manager at a marketing agency will have anywhere from as few as five clients to more than 40. Of course, the more clients one person has, the less attention they will have for your business. And never mind their ability to keep up with all of their clients, their varying needs, demands, and performance levels. 

4. Are account managers generalists or specialists?

For the most part, you want someone working for you who has specific industry knowledge. After all, how does someone who knows nothing about, say, the senior care industry help market a senior living home? Especially since that person is probably also managing the accounts a senior living home, a dental practice, a computer chip manufacturer, an automotive parts retailer, and an artificial intelligence software company. It's going to be difficult not only to learn all of them well enough to market them successfully, but also to keep up with five very different industries simultaneously. 

5. Do you work for my competition? 

On the other hand, marketing agencies that offer specialists may be marketing both you and your competition. This is as common among local agencies marketing local businesses as it is among large, national marketing agencies that focus on providing marketing services to those within a specific industry. And if this happens, so much for your marketing agency giving you any sort of competitive advantage. 

The process of hiring a marketing agency might feel a lot like interviewing candidates for employment. Because that is what you are doing. It's arguably more important because with hiring a marketing agency--as opposed to an individual marketer--the person you're speaking with is likely not the same person who will actually be doing the work your business is paying for.

By approaching agencies the way you would approach hiring a candidate (e.g., using Elon Musk's brilliant two-hands test) and asking these questions before hiring an agency, you know exactly what you are getting and what you can expect out of your relationship with them. In return, you'll more easily find the best marketing agency for your business and start off on the right foot-with transparency, trust, and integrity.