TCC plans definitely work...the workouts are not easy though
The plans last for around 10-12 weeks, with 2-3 high-intensity workouts each week.
After the plan ends, you will need 6-8 weeks of less intense cycling (e.g. endurance and tempo rides) to recover and maintain some fitness. This is explained in the book, however, there is no plan in the book for this period, so you will just have to work this out for yourself.
After 6-8 weeks of less intense workouts, your legs should feel fresh again, and you can then select another high-intensity plan to take you to the next level