It’s common for thyroid hormone needs to change over time. There are many reasons why our body either metabolizes the hormone differently or our needs change for thyroid hormone — some of the factors can be age, weight, activity level, hormonal status (menopause, for instance), or stress levels. It is best to be checked at least annually, to be sure that our hormone needs are being met (and not exceeded).
~Ski
NGDF Assistant Online Facilitator