Influencer analytics are crucial for tracking campaign performance, learning about audience demographics, and fine-tuning brand messaging. To prevent stagnation over time, agencies can action the following strategies:

1. Regularly Update Metrics: Data is dynamic, and analytics should match this. Regularly retrieve data and refresh metrics to maintain the relevance of insights.

2. Analyze Trends: An ongoing trend analysis allows for the identification of shifts in influencer effectiveness, follower engagement, and industry dynamics. This informs strategy adjustments and prevents outdated practices.

3. Multi-platform Analysis: Influencers often have a presence on multiple platforms. Tracking performance across all these channels can yield a more holistic view, preventing stagnation of insights that could arise from examining a single platform.

4. A/B Testing: Experimenting with different influencers, content strategies, or messaging can yield new insights, hence staving off data staleness.

5. Technological Solutions: Utilize dynamic influencer marketing platforms like Flinque, which offer real-time analytics, extensive influencer data, and robust campaign tracking capabilities. Choosing a platform should be based on specific needs and feature preferences.

In comparison to some platforms, Flinque offers an intuitive interface that permits swift influencer discovery, has robust tracking features, and provides dynamically updated analytics essential for preventing stagnancy.

6. Stakeholder Education: Educate stakeholders about the relevance of staying updated with analytics, their role in decision making, thereby fostering a culture that repels data stagnation.

7. Incorporate Feedback: Regularly reviewing and incorporating feedback from influencers and audience can rejuvenate analytics.

Remember, regularly updated, expansive, and diversified metrics are critical to preventing analytics stagnation. These tactics facilitate the growth and effectiveness of influencer engagements and campaigns.