In the ever-evolving world of digital marketing, brands are competing fiercely to maintain customer loyalty and maximize lifetime value. Retention marketing — the strategy focused on nurturing existing customers — has become indispensable in 2025. With rising customer acquisition costs, businesses must now evaluate the effectiveness of different communication channels more critically than ever before. Among the top contenders in the retention toolkit are SMS, email, and push notifications. Each offers unique benefits, limitations, and best-use scenarios. But how do they stack up against each other in terms of engagement, cost-effectiveness, personalization, and scalability?
What is Retention Marketing?
Retention marketing is the art and science of keeping customers engaged and buying after their initial interaction. Rather than always focusing on acquiring new users, smart marketers today prioritize building deeper relationships with their existing audience. Tactics for retention include loyalty programs, follow-up communication, customer support enhancement, and content delivery through various channels — primarily SMS, email, and push notifications.
Key Metrics for Evaluating Retention Channels
Before comparing these communication methods, it’s important to understand how their success is evaluated. Some key performance indicators (KPIs) include:
- Open Rate: How many users actually open the message
- Click-Through Rate (CTR): How many users interact further by clicking a link
- Conversion Rate: How many users complete a desired action
- Unsubscribe/Opt-Out Rate: Indicates channel fatigue or dissatisfaction
- Cost per Engagement: Measures efficiency in terms of ROI
SMS Marketing
Short Message Service (SMS) has reemerged as a high-performing channel for retention due to its directness and immediacy. In 2025, nearly 95% of global consumers own a mobile phone capable of receiving SMS — giving brands unparalleled access.
Pros:
- High Open Rates: SMS messages have an open rate exceeding 98% within the first few minutes.
- Real-Time Engagement: Great for time-sensitive offers like flash sales or appointment reminders.
- Personalized Opportunities: Short, tailored messages can resonate powerfully with the audience.
Cons:
- Character Limit: Sticking to 160 characters can be creatively stifling.
- Intrusiveness: Users may find SMS too direct or disruptive, risking higher opt-out rates.
- Costlier: Especially when messaging large lists, SMS can be more expensive than other channels.
Best Use Cases: Last-minute promotions, appointment reminders, shipping alerts, subscriber-only exclusives.
Email Marketing
Email remains the workhorse of digital marketing in 2025. Despite debates about email fatigue, it continues to deliver exceptional ROI, particularly for longer-form content and complex promotional offers.
Pros:
- Scalability: Ideal for sending campaigns to large, segmented audiences.
- Rich Content Capabilities: Supports multimedia, links, and detailed copywriting.
- High ROI: Delivering up to $42 for every dollar spent, per industry averages.
Cons:
- Lower Open Rates: Current benchmarks place average open rates at around 20-25%.
- Inbox Competition: Users are flooded with emails daily, making it harder to stand out.
- Spam Filters: Risk of emails landing in promotional or spam folders is always present.
Best Use Cases: Newsletters, cart abandonment flows, onboarding sequences, promotional campaigns, and customer feedback requests.
Push Notifications
Push notifications, both in-app and web-based, have gained traction for their ability to deliver messages instantly without relying on traditional inboxes. Especially popular in mobile-first industries, push is increasingly used as part of omnichannel retention strategies.
Pros:
- Instant Visibility: Users receive alerts right on their device screen.
- Behavior-Triggered: Excellent for real-time targeting based on user interaction.
- Low Cost: Extremely affordable to send, especially when compared to SMS.
Cons:
- Consent Required: Users must opt in, and many initially bypass permission prompts.
- Limited Content: Push messages are brief and can’t support rich content.
- Risk of Annoyance: Poorly timed or overly frequent messages lead to quick opt-outs.
Best Use Cases: App usage reminders, low-stock alerts, content updates, milestone achievements, and loyalty rewards.
Channel Performance Comparison in 2025
To better visualize how these channels stack up, here’s a quick comparison based on industry trends and real-world data in 2025:
| Metric | SMS | Push Notifications | |
|---|---|---|---|
| Open Rate | 98% | 22% | 80% |
| CTR | 19% | 2.5% | 4.2% |
| Opt-Out Rate | 6% | 0.3% | 8% |
| Cost | High | Low | Very Low |
| Personalization | Good | Excellent | Moderate |
Trends to Watch in 2025 and Beyond
Retention marketing channels continue to evolve, fueled by AI, automation, and changing user habits. Here are some key trends shaping the SMS vs email vs push conversation:
- Hyper-Personalization: AI-driven insights enable brands to create persona-based messaging across all channels.
- Cross-Channel Integration: Rather than relying on one method, marketers are blending all three channels into seamless journeys.
- Privacy Regulations: As data privacy laws tighten, channels like email and push will favor brands that practice ethical data collection.
- Interactive Content: Innovations like AMP emails, tappable push messages, and SMS surveys are enhancing engagement.
Choosing the Right Channel
No one channel is objectively superior — the right choice depends on your goals, audience, and message. Here’s a quick guide:
- Use SMS if: You need urgency, direct attention, or are running time-sensitive campaigns.
- Use Email if: You want to build long-term engagement with detailed content and rich storytelling.
- Use Push if: Your users are app-centric or web-based, and you want to drive frequent repeat usage.
Conclusion
In 2025, retention success lies not in choosing one channel over others, but in knowing how and when to use each. SMS offers immediacy, email delivers depth, and push excels at contextual outreach. Forward-thinking brands are leveraging data to deliver the right message, via the best channel, at the perfect moment. Investing in a smart, coordinated omnichannel strategy can lead to powerful increases in customer loyalty and lifetime value.