Email marketing is a delicate balance: You want to keep in touch with customers and prospects and stay top of mind, but you don’t want to pester them with information they don’t need. You want to achieve a steady stream of leads without too many spam reports or unsubscribes.

We all know how it feels to be on the receiving end of too many useless emails, so it’s good to be sensitive to email marketing frequency. However, we’ve seen many companies take such a cautious approach to email that they miss out on valuable opportunities to nurture prospects and generate sales.

Email is still by far the most cost-effective way to acquire new leads, nurture prospects and retain customers. In fact, every dollar spent on email generates an average ROI of more than $44, according to ExactTarget.

So how often should you send emails?

It’s a question our clients often ask, but it may not be the right question to ask. Here are five questions you should be asking instead.

What Are My Marketing Goals?

Are you looking to grow your existing database? Consider partnering with another relevant company in your industry on a series of joint emails that will allow you to broaden your reach. If your primary audience is human resource professionals, consider sponsoring some content in the Society for Human Resource Management’s monthly e-newsletter.

Looking to nurture a group of potential clients who visited your booth at a recent trade show? This group will likely be more receptive to your mssages because they’ve already shown interest in what you do, so you can contact them with a bit more frequency. You could send a series of follow-up emails once a week to share a few relevant resources and an invitation to learn more.

Another goal might be to re-engage current customers with a new offer or a special deal that’s only available to them. Similar to the list of trade show contacts, you can engage them with an email campaign that includes several targeted messages spread out over a period of time.

If your company has a particularly long sales cycle, perhaps a year or longer, your goal may be simply to promote your thought leadership in the industry so you stay at the top of their minds. In that case, a monthly blog digest might be better received than weekly emails.

What’s Typical For My Industry?

If you’re marketing directly to consumers, you’ll probably get away with emailing more frequently. Personally, I receive emails to my personal inbox several times a week from the same retailers. I let most of them pile up in my inbox unopened, but they don’t bother me enough to unsubscribe or think any less of that retailer. Every once in awhile, I’ll open one if I see a deal on something I’m interested in buying.

I’m much more protective about messages that come to my work email address, and I suspect many people are the same way. Within the B2B realm, frequency also varies by industry. In general, technology companies tend to mail a bit more frequently than manufacturers and healthcare companies, but it really depends on the sales cycle.

It’s worth watching a few of your competitors to see what seems to be typical, but don’t be afraid to try a different approach.

What Is The Quality Of My Email Database?

Consider how you acquired the email addresses in your database. Are they mostly contacts who have shown interest in some way, whether it was by subscribing to your blog or attending an event? Or did a significant portion of them come from purchased lists?

If the majority of your email contacts haven’t “opted in” in some way or you aren’t sure where they came from, it might be time to clean up your database. Considering the fact that about one-third of all email contacts churn each year, due to people changing jobs or email addresses, it’s a good idea to do an audit of your list at least once a year. Send an email asking your contacts to update their preferences and give them the opportunity to opt out if they are no longer interested in hearing from you.

Don’t worry too much about losing contacts this way—chances are, they’re not going to become customers anytime soon, and you’re making room for others who are more likely to buy.

How Have Past Emails Performed?

Take a look at the results from your email marketing efforts over the past year. How were the open rates and click-through rates compared to industry averages? If you have increased your email frequency, how has that impacted those rates?

Additionally, consider your email marketing goals and how close you are to achieving them. If your goal is to increase your sales-ready leads by 5 percent over the next six months and you’re nowhere close to that, you might need to up the email frequency.

What Is My Ability To Target?

No matter who you’re targeting, you’ll get the best response when the emails you send are tailored to that person’s unique interests and challenges. It’s also important to establish the right tone for the person you’re trying to reach, rather than sending everyone the same message. Have you developed buyer personas and segmented your email list accordingly?

Are you using marketing automation software that allows you to segment your lists based on those preferences and the activities of those who engage with you? Just as you wouldn’t talk to a CEO in quite the same way as you might talk to a human resources manager, you don’t want to send an introductory-style email to someone who has already visited your website several times and downloaded a recent piece of content.

One of the biggest advantages of marketing automation software is the ability to establish email workflows to nurture customers and prospects at every stage of their journey, from the time they first show interest to after they’ve made a decision. Since buyers now do the majority of their research before they ever talk to a sales representative, email is one of the most important ways to keep them engaged.

The Bottom Line

When it comes to email marketing, there is no magic number. At Kuno, we typically send emails at least once or twice a week, but not to our entire database. Rather, we’re sending workflow emails to some people who have recently downloaded something, emails to blog subscribers who have selected particular areas of interest, and emails to another group of people to promote a new eBook or webinar. We recently asked our blog subscribers to update their preferences so we could provide more relevant content based on their industry and what they indicated they were most interested in seeing.

On average, these types of lead-nurturing emails generate 50 percent more sales-ready leads at 33 percent lower cost, according to HubSpot. The research also shows nurtured leads produce a 20 percent increase in sales opportunities compared to those who aren’t contacted regularly.

The key is to be consistent and be persistent—even if you don’t see the results you want right away.