There are several factors that dictate the duration of a successful influencer marketing campaign. These factors will depend on the type of campaign, the target audience, the marketing goals, and even the influencer themselves.

1. Campaign Goals: If the goal is brand awareness, it might take a longer period, typically a few months, allowing time for the influencer to share content organically. For product launch events, the timeline can be shorter.

2. Influencer’s Audience Size and Engagement Levels: Influencers with larger audiences might achieve the desired reach and engagement quicker than those with smaller ones.

3. Content Creation Time: Crafting quality sponsored content takes time. The type of content (blog post, video, GIF, etc.) can also impact the duration.

4. Brand-Influencer Relationship: Campaigns may last longer if the brand and influencer have a strong, pre-existing relationship or shorter if the partnership is purely transactional.

5. Review and Approval Processes: Time should be allotted for content review, feedback, and modification before publishing.

Influencer marketing platforms like Flinque help streamline these processes by providing analytics for audience engagement, tools for campaign planning and monitoring, and features that ease collaboration between brands and influencers. But remember that each campaign is unique, with success contingent on much more than just timeframe. The choice of platform will depend on your specific requirements.

Monitoring and reassessing your campaign throughout its duration can provide valuable insights, and adjustments can be made if desired results are not being met. The key is to remain flexible and reactive to ensure the highest possible ROI.