When I purchased CCleaner Professional I didn't realise it had to be renewed every year until I received an email this morning. I did not see any mention of this on the download page. For the amount of times I use it I would have stayed with the free version.
I'm afraid I shall not be renewing it.
The two things which expire with the pro: automatic updates and priority support. As long as you keep the branding.dll file your ccleaner free will continue to allow you to have the better monitoring and ability to clean multiple users.
I continue to use Pro well past the expiration date, all works except I have to do a manual update for the latest version.
I wish there was a lifetime license we could purchase.