One of the most frequent questions I get from business owners is some variation of the following: “should I be spending money on SEO or PPC?”

It’s a complex question, and there’s no one right answer. But I can help you understand the factors you’ll need to consider when making the decision for yourself.

The basics: SEO vs. PPC

We’ll start with a basic explanation for anyone not familiar with these strategies.

SEO stands for search engine optimization. We all use search engines on a regular basis to find what we’re looking for, whether it’s an answer to a question about history or a link to a store that sells a specific type of boot. SEO is all about optimizing your site to rank higher in search engines so your target audience will be more likely to discover it when searching for terms relevant to your industry. Typically, that means using a combination of technical onsite changes (i.e., coding tweaks on the backend), high-quality onsite content and offsite link building efforts to boost your perceived authority and relevance in the eyes of Google (and other search engines).

Related: 3 Tips on Becoming a Pay-Per-Click Expert

PPC stands for pay-per-click advertising. The idea here is to use a platform like Google, Facebook, or Bing to place ads that your target audience will see. You’ll pay a set amount for each person who clicks on that link (hence the name of the strategy). On the backend, you’ll have total control over how those ads appear, how they’re written, who they’re targeting and more.

Both these strategies are common in the digital marketing world and both of them are relevant to search engines, though they require fundamentally different approaches. This leads many people to assume they’re somehow opposites, or that you have to choose one over the other; in reality, SEO and PPC are at their best when working together.

Still, there are pros and cons to each.

Where SEO shines

SEO has several advantages over PPC, such as:

Long-term cost efficiency and ROI. For the most part, SEO is more cost-efficient than PPC ads, especially over the long term. It takes a while for an SEO strategy to start building momentum, since it takes time to create content, build links, and increase your domain authority in the eyes of search engines. But once that momentum is there, you’ll start generating impressive returns.

Credibility and organic appeal. You’ve seen ads in Google before. What do you think of them? If you’re like most people, in most cases, you skip past the ads immediately and move to the organic search results. That’s because organic search results have higher perceived credibility and more immediate consumer trust; this makes SEO a great way to make sure your business gets seen as a genuine authority.

Competitive dominance (eventually). In the PPC world, anyone can get their ad listed for a given term if they spend enough money. But in SEO, you can’t buy your way in (at least, not as easily). Once you’ve established yourself as the ultimate authority for a given niche, you’ll find it easy to maintain that competitive dominance. Of course, getting there can be difficult.

Peripheral benefits. SEO requires you to build links, write good content, and make your site more user-friendly; this gives SEO a host of peripheral benefits, and the potential to support many other marketing strategies.

Related: 7 Reasons Why SEO Matters for Every Startup

Where PPC shines

There are also some important ways that PPC is advantageous over SEO:

Immediate effectiveness. You don’t have to wait months (or weeks, for that matter) for your PPC strategy to “kick in.” You’ll start seeing your ads placed in search engines as soon as you start paying for them, making PPC a faster strategy overall.

Guaranteed results. With SEO, there’s a bit of luck and hope involved. But in the PPC world, there’s no such guesswork. You only pay for the clicks you actually receive, so in a way, you’re guaranteed results.

Fine-tuned controls. PPC offers much more fine-tuned controls over your strategy. You can target exactly the audience you want to reach – and test your ads to see how effective they truly are.

Possible entry points. Established SEO competitors are tough to topple. But with sufficient budget and the right targeting, PPC ads can displace practically any competitor.

Related: 9 Mistakes Killing the Success of Your Pay-Per-Click Advertising

The bottom line

If you want to grow your business as quickly and efficiently as possible, you should use a combination of both SEO and PPC ads. Each strategy has strengths and weaknesses that complement the other – and by using both, you can maximize your search engine coverage. That said, certain aspects of your business should push you to favor one strategy slightly more than the other; for example, if you have a limited budget and a long time horizon, SEO is the better option, while if you have immediate needs for increased traffic, PPC ads are superior.