Hi Ploh and Mei!
Purchasing a BrillKids learning system entitles you to LIFETIME usage of the software, which means you will be able to continue using it even after you've finished your payment installments. There is no time limit for when you need to finish the lessons, and you can take your time in teaching your little one. You can even reuse the program to teach your future children, if you'd like!
The Semester 1+2 (12-month) curriculum or Semester 1 (6-month) curriculum only dictates the amount of lesson content we will provide you. This is similar to buying a book with 100 pages; the pages will still be there once you have finished reading the book, and you can reread and revisit the pages whenever you want.
When you finish the Curriculum, or when you've finished paying your installments already, you can continue using your learning system -- you may choose to review certain lessons from your curriculum, or you may start creating your own (additional) lessons on different topics or in another language that you'd like to teach your child.
I hope this clarifies things for both of you. Let us know if there's anything else that you need help with!