Boost Duration extends the time you have between Rituals in a given batch to 28 days or until the next Ritual of the appropriate aspect is cast, whichever comes first. During the 28 day duration, Boost Duration items are indestructible by normal means.
This Ritual will only affect a Ritual Batch if it is cast as the last Ritual in the Batch and is of the same Aspect as those Rituals cast in the batch prior to adding Boost Duration. Boost Duration effectively holds the Batch open and at any time during the 28 day duration of this Ritual, additional Rituals can be cast onto the item and, if they are of the same Aspect as the Boost Duration, they will be considered part of the same Batch as those Rituals affected by the Boost Duration. An Extender Ritual of the appropriate Aspect (such as Preserve Duration or Permanent Duration) will replace the Boost Duration if cast on the Batch within the 28 days and will affect all Rituals of the appropriate Aspect on the item (considering them a single Batch) regardless of when during the 28 days they were cast into the item.
Unlike other Extend Rituals Boost Duration will allow a Preserve Duration or Permanent Duration Ritual to be cast at any time before the expiration of the Boost Ritual to further Extend the Rituals of the batch. Any Extenders cast into a batch with the Boost Duration will replace the Boost Duration if it is of the same Aspect. If the Boost Duration Ritual expires or is not replaced it will simply fade from the item without any consequences other than the loss of the ability to further Extend the Batch.
While an item has an active Boost Duration you cannot add an extender of the same Aspect without replacing the Boost Duration. You must finish the Boosted Batch with an Extender before you can begin/extend another batch of the same Aspect on an item. The Difficulty of the Extender which is cast to replace the Boost is calculated off the total number of Rituals to be affected not including the Boost Duration Ritual (as it is overwritten by the new Extender).
There is no limit (other than the typical maximum Rituals per item) to the amount of Rituals that can receive a Boost Duration. You cannot cast a Boost Duration Ritual on any other form of Extend Duration Rituals to extend the time you have to add Rituals or add an Extend Ritual to an existing Ritual batch. You cannot cast Boost Duration over an existing Boost Duration. If the Boost Duration expires before the duration of the Rituals that it was cast on the batch can no longer be augmented with an additional extender or Rituals however any Ritual which has not expired will still function until their normal Duration expires.
Note: Logistics activations are still used if the Batch is checked in into an event while the Boost Duration is active.