Keeping up with SEO (Search Engine Optimization) best practices is a challenge for most businesses. Google always seems to have a major algorithm change on the horizon -- not to mention the changes they make without telling anyone.

Hiring a firm can be a valuable way to ensure your business stays on top of the SEO game but only if you find the right one. Here are 10 questions you should ask any SEO firm before signing on.

1. What SEO services do you offer?

SEO encompasses a lot of different tasks. You need to have a clear understanding of what the firm will be responsible for and what tasks are left for you. Which technical, off-page and on-page tasks are they prepared to handle? And since SEO, content marketing and PPC (Pay-Per-Click) are so interconnected, you might want to find a firm that’s set up to help you out with all three.

Related: Here's What Really Matters for SEO in 2016

2. Do you have case studies that demonstrate your work in action?

Any SEO firm worth your time will have plenty of case studies and a portfolio of happy clients for you to look at. You should be able to see how some of their current clients are ranking well or at least significantly improving their rank. At the very least, they should be able to demonstrate the effectiveness of their own site in search results. If they lack this evidence, it’s a red flag.

3. How exactly will you increase my organic traffic?

This is an important question to ask, because there are a lot of ways to create temporary holes in rankings that aren’t sustainable long-term. Specifically, you’ll want to know whether or not the firm will follow Google’s best practices to safeguard you from penalties later on. A high quality firm should be able to provide you with a clear outline of their action plan to increase your organic traffic.

4. What tools do you use?

There are many tools SEO firms can use, including tools for keyword research, technical SEO tools like site crawlers and reporting tools. Make sure you have a clear understanding of what each tool is used for. Some tools, such as forum scrapers and link building tools, are often used for black hat SEO, but they can have some white hat purposes as well.

5. What about link building?

Link building is a touchy subject, because a lot has changed recently regarding how to optimize for this ranking factor. Unnatural backlinks from low quality sites can harm your SEO. Natural links from high authority domains can help. If the firm is taking on link building as part of their services, you should know how they’re going about it. In most cases, getting high authority links will require business clout, not the firm’s.

Related: 6 Advanced Techniques for Link-Building as a Future SEO Strategy

6. How often will you report your work?

There are many key performance indicators you can monitor to see how your efforts are going. You’ll want to know how often the firm plans to report back to you about these SEO metrics. It’s worth noting that leading marketers tend to check their metrics more often than those lagging behind:

7. How can I track the changes you make to my website?

When you hire an SEO firm, you have no choice but to give them access to your website. That’s why it’s important to find a firm you can trust, and make sure they’re prepared to report on whatever changes they make to your site. They should keep a log of all changes made so that you can refer to it at any time if something goes wrong or if your SEO firm becomes unresponsive.

8. What can you promise me if I use your services?

If their answer to this question is disappointing, it should be. An SEO firm just trying to make a sale will happily tell you that they’ll get your site ranking number one for a certain keyword. But it’s just impossible to know that. No one knows how many ranking factors there are, when more will be introduced or when then next algorithm update will be. The firm shouldn’t be able to make any guarantees for SEO. If they do, it’s time to walk away.

Related: 7 Red Flags Your SEO Firm Is Going to Rip You Off

9. What is your payment structure?

Does the firm charge per project, per hour, monthly? If they provided you with an outline of their SEO plan, you can ask for an estimated cost for the whole project as well. Also, keep in mind that anyone can call themselves an SEO expert. If you find a firm with seriously lower prices than the others, that might be a red flag in and of itself.

10. Can you demonstrate my ROI from this investment?

According to Hubspot, proving ROI is the biggest challenge inbound marketers face today.

And since demonstrating ROI is key to unlocking a marketing budget, you can’t afford to have a question mark when it comes to your SEO firm. If their activity tracking and analytics are up to snuff, your SEO firm should be able to show you the exact payoff for your money spent.

Know any other important questions you should ask an SEO firm before signing on? Share your suggestions by leaving a comment below.

Images: Softloom, Hubspot