Which tool is recommended for sending a series of emails for a 90-day trial subscription reminder?

The best choice for sending a series of emails for a 90-day trial subscription reminder is Playbooks. Playbooks are designed to help marketers manage and execute complex campaigns effectively. They allow for structured planning and organization of email sends over a specified timeline, making it ideal for a reminder series that is time-sensitive, like a trial subscription reminder.

Using Playbooks enables the marketer to create a flow that includes multiple emails scheduled to go out at specific intervals throughout the 90-day period. This structured program helps ensure that recipients receive timely reminders, enhancing their experience and increasing the likelihood of conversion.

Other options may not be as suitable for this particular need. Automation Studio is typically used for more complex automation scenarios or workflows, allowing for the management of various automation tasks, but it may require more configuration than needed for a straightforward reminder series. Guided Send is more focused on sending individual emails based on user interactions rather than a timed series. Triggered Emails are designed for immediate responses to specific actions or events rather than for scheduled reminders over an extended timeframe. Hence, Playbooks provide the best framework for the planned approach required for this email campaign.