How does infrequent email sending impact deliverability and what strategies can be used to mitigate these effects?
Michael Ko
Co-founder & CEO, Suped
Published 20 May 2025
Updated 16 Aug 2025
7 min read
Infrequent email sending can feel like a deliverability tightrope walk. You want to connect with your audience, but if your email volume is inconsistent, internet service providers (ISPs) and even your subscribers might view your messages with suspicion.
ISPs, such as Google and Microsoft, rely on consistent sending patterns to build a trustworthy sender reputation. When your email volume fluctuates dramatically, it can raise red flags, making it harder for your messages to reach the inbox. It's like trying to build a consistent relationship when you only show up every few months.
In this guide, we'll explore the specific ways infrequent email sending impacts deliverability and outline practical strategies to mitigate these effects. By understanding the challenges and implementing proactive measures, you can ensure your emails consistently land in the inbox, even with an irregular sending schedule.
The impact on sender reputation
ISPs use advanced algorithms to assess the trustworthiness of sending domains and IPs. A key factor in this assessment is consistency. If your domain or IP (internet protocol) address sends millions of emails one month and then goes quiet for two months, only to burst back with another huge send, it doesn't build a strong, positive domain reputation.
This erratic pattern can look like a hit and run approach to sending, often associated with spammers trying to dump large volumes of messages before their IP or domain gets blocklisted (or blacklisted). Machine learning filters employed by ISPs are designed to detect such unusual behavior.
Without consistent sending, ISPs have less data to evaluate your legitimate sending practices. This lack of positive data points makes it difficult to maintain a good sender score, leading to increased scrutiny and a higher likelihood of your emails landing in the spam folder.
Furthermore, if you're using a dedicated IP address, it requires consistent volume to build and maintain its reputation. Sending infrequently means your dedicated IP won't stay warm, increasing the risk of deliverability issues when you do send. This is why some recommend getting off a dedicated IP for very infrequent, high-volume sending.
Infrequent sending red flags
Low frequency: Sending only once every few months with large volumes can appear suspicious to ISPs.
Reputation decay: Sender reputation can degrade during long periods of inactivity, making it harder to deliver when you resume.
Dedicated IP warming: A dedicated IP needs consistent mail flow to maintain its warmth and trustworthiness.
Challenges with large, infrequent sends
One of the most significant challenges for infrequent senders is the risk of subscribers forgetting they opted in. When your messages arrive after a long silence, recipients may not recognize your brand, leading to higher rates of spam complaints and unsubscribes. This negative engagement significantly harms your sender reputation, according to Klaviyo.
Sending to inactive or unengaged contacts also poses a substantial risk. Over time, email lists can accumulate invalid addresses, typos, and even spam traps. Hitting these can lead to high bounce rates and immediate blocklisting (or blacklisting) of your IP or domain, severely impacting your ability to reach the inbox.
The combination of subscriber forgetfulness and a potentially stale list means that large, infrequent campaigns are prone to poor engagement metrics. Low open rates, high complaint rates, and high bounce rates send negative signals to ISPs, further damaging your reputation and increasing the likelihood of future emails being filtered into spam.
The problem: infrequent sending
Lost subscriber memory: Recipients forget they subscribed, leading to spam complaints.
Stale email lists: Accumulation of invalid addresses and spam traps.
Reputation erosion: ISPs view sporadic, high-volume sending as risky behavior.
The solution: strategic adjustments
Re-engagement campaigns: Nurture dormant segments before major sends.
List validation: Regularly clean your list to remove bad addresses.
Consistent volume: Maintain a baseline sending pattern, even if low.
Strategies for successful infrequent sending
The most effective strategy is to establish some form of consistent sending, even if it's at a very low volume. This helps maintain IP and domain warmth and provides ISPs with regular data points to build a positive sender profile. MailerLite emphasizes that consistent sending helps avoid spam. Consider sending a monthly newsletter, small updates, or transactional emails that keep your domain active, even if your main campaigns are quarterly or seasonal.
For the specific large campaigns, implementing a controlled ramp-up (or warming) is crucial. Instead of sending all 4 million emails at once, gradually increase your volume over several days leading up to your target delivery date. Start with a small, highly engaged segment of your list and slowly expand. This mimics natural sending patterns and helps ISPs adjust to your volume without flagging it as suspicious.
Crucially, maintain impeccable list hygiene. Regularly clean your email list by removing inactive or unengaged contacts. This reduces bounce rates and prevents you from hitting spam traps, which are detrimental to your sender reputation. For very infrequent senders, a re-engagement campaign before a major send can help identify active subscribers and prune dormant ones.
Key strategies for infrequent senders
Warm-up period: Before large infrequent campaigns, gradually increase sending volume over several days.
List segmentation: Target your most engaged subscribers first to build positive signals.
Engagement strategies: Focus on highly relevant content that encourages opens and clicks.
Double opt-in: Ensure your subscriber acquisition methods are robust to prevent complaints.
Technical adjustments and monitoring
The choice between a dedicated IP and a shared IP can significantly impact deliverability for infrequent senders. A dedicated IP needs constant, consistent mail flow to maintain its reputation, which is challenging with infrequent large sends. In such cases, a shared IP might be more suitable, as its reputation is maintained by the collective sending of many users, buffering the impact of your sporadic sending.
Regardless of your IP choice, implementing proper email authentication protocols is non-negotiable. SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting, and Conformance) records verify your sending legitimacy. These protocols tell ISPs that your emails are truly from your domain, building trust and reducing the likelihood of being marked as spam or getting on a blocklist (or blacklist).
Monitoring your deliverability is paramount. Use tools to track your inbox placement rates, spam complaint rates, and bounce rates. Pay close attention to any fluctuations following your sends. This data will provide insights into how ISPs are perceiving your sending patterns and allow you to make necessary adjustments quickly.
Finally, consider the actual message content. Personalization and relevance are even more critical for infrequent senders, as they combat subscriber forgetfulness. High engagement signals (opens, clicks, replies) reinforce a positive sender reputation, helping to counteract the challenges posed by irregular sending volumes. Avoiding common spam triggers, such as excessive images or problematic keywords, is also essential.
Authentication protocol
Purpose
Impact on deliverability
SPF (Sender Policy Framework)
Authorizes specific IP addresses or domains to send email on behalf of your domain.
Prevents spammers from forging your sender address, crucial for trust.
DKIM (DomainKeys Identified Mail)
Adds a digital signature to your emails, verifying content integrity during transit.
Ensures that email content hasn't been tampered with, boosting authenticity.
Instructs receiving servers how to handle emails that fail SPF or DKIM checks, and provides reporting.
Offers visibility into email authentication failures and protection against phishing.
Views from the trenches
Best practices
Maintain a small, consistent email flow even between large campaigns to keep your IP/domain warm.
Segment your list to send to the most engaged subscribers first during large infrequent sends.
Implement a gradual warm-up process for each large campaign, increasing volume over several days.
Routinely clean your email list to remove inactive subscribers and potential spam traps.
Common pitfalls
Sending massive email blasts after long periods of inactivity, triggering spam filters.
Using a dedicated IP address without maintaining a consistent, daily sending volume.
Ignoring engagement metrics (opens, clicks) for infrequent campaigns, signaling low interest to ISPs.
Failing to implement proper email authentication (SPF, DKIM, DMARC) for all sends.
Expert tips
Dedicated IPs require mailing multiple times a week to establish and maintain reputation.
For large, infrequent sends, throttle the volume over several days, treating each send as a warm-up.
Consider a shared IP if consistent sending isn't feasible, as its reputation is maintained by collective volume.
Machine learning filters prioritize consistent sending patterns and are wary of sudden spikes in volume.
Expert view
Expert from Email Geeks says a hit and run 4 million send every three months is likely to result in poor delivery.
2021-10-27 - Email Geeks
Expert view
Expert from Email Geeks says dedicated IPs need to be mailed multiple times a week to maintain a good reputation.
2021-10-27 - Email Geeks
Navigating infrequent sends for success
While infrequent email sending poses unique challenges for deliverability, it's not an insurmountable obstacle. The core principle is to demonstrate consistent, trustworthy sending behavior to ISPs, even if your major campaigns are sporadic.
By actively managing your sender reputation through consistent (even low) volume, meticulous list hygiene, strategic warming, and robust authentication, you can significantly improve your chances of reaching the inbox. Adapting your sending practices to accommodate the nuances of infrequent schedules is key to long-term email marketing success.
Google and 
Microsoft, rely on consistent sending patterns to build a trustworthy sender reputation. When your email volume fluctuates dramatically, it can raise red flags, making it harder for your messages to reach the inbox. It's like trying to build a consistent relationship when you only show up every few months.
