You can renew ahead of time if you want to:
Before your license expires, you will receive a small number of notifications at the email address associated with your license and from the CCleaner software itself, so you do not need to worry about ‘missing out’.
You’re welcome to make use of these notifications to renew your license early if desired; renewing a license while it’s active will simply add the purchased period of time (typically 1 year) to the license.
Note: Purchasing directly from the CCleaner website will provide you with a new license that will start on the date of purchase; this is intended for use on an additional computer, for instance.
Please feel free to contact support to ask about renewing at an earlier date, or to inquire if a particular promotion is suitable for renewals, or if it is for new purchases only.