I installed CCleaner quite a long time ago and have CCleaner Professional, currently V4.09.4471.
I believe I must have paid for this,as it has the "Professional" label, but embarrassingly I can't remember.
This has arisen because an email advising me of the latest update arrived this morning, promising goodies and offering a discount if I upgrade.
Have I paid and is it a one off payment ?
There is no "Account detail" shown on the PiriformCCleaner "box".
Having seen the answer to the post below, I see it is an annual subscription.
How do I know when mine runs out ?
I've no idea. These questions would be better being made to the Piriform Support team. You can get details of your support key here http://www.piriform.com/support/license-lookup then you can ask for a renewal date.
I have now put the question in to the Support Team, but it does seem strange that the subscription expiry date is not available somewhere, which is what makes me think I have missed something.