For Annual plan, can unused learner licenses for any particular month be carried over?

For the Annual plan, unused learner licenses for any particular month cannot be carried over to the following month(s).

Consider adding Flex-Learners to your plan. Each Flex-Learner is equivalent to 1 Learner-Month, i.e. 1 unique learner’s access to ArcLab for 1 month, and can be utilised anytime within 12 months. More details here.