With the exception of some courses which naturally expire or become obsolete, as long as you have an acitve account and membership plan you will have access to your purchased online courses. Note that free membership plans have less extended access to courses than paying membership plans.
As of December 2023, some courses will be moved over to a new course platform. Provided you apply for the new course platform before your course expires and before the migration to the new course platform, then your course access can be transferred over. Read more about this migration and register for the new online course platform here!