You have 24/7 access for 12 months from the date you register on the site. You can check your registration i.e. expiry date in your "My Account" section. You can access "My Account" section by clicking on your name on the top right corner of any page after log in.
Please note the "Time to complete" on your dashboard is just an estimate f how much study time you'll need to finish the course.
If you purchased a monthly subscription, your access is renewed every month upon payment receipt.