The future perfect continuous tense is used when you want to emphasize an event or activy that be continuous after specific future time.

The future perfect continuous verb tense is used to:

• Emphasize - how long an event will be in progress at a future time
• Stress - the the length of time an event or action in the future
• Results - used to state the results of an action or event in the future.
• Represents A Continuous Action - that stated at some point, and continues into some point in the future

Rules for using the future perfect continues verb tense:

The future period of time if usually states:

• next year
• next week
• next month etc.
• the exact came can be stated
• the approximate can can be stated

The future perfect continuous verb tense is usually not used with static verbs.

The future perfect continuous verb tense can't be used with "time clauses" such as when, while, "by the time", soon, before, after, if, unless, until etc.

Examples:

• In the fall, I will have been studying here for 2 years.
• My son will have been in teaching for 10 years next month.
• The teacher will have been teaching my children for 5 years next month.
• Tammy will be very tired when she comes home, because she will have been flying over 24 hours.