Your Inklingo downloads never expire, so you can take as much time as you like to finish your quilts.
You get 200 days is "offline" access (when you are not "online") at a time. If you open one of the PDFs (shape collections or design books) and it has been longer than 200 days, you will be prompted to enter your email address and password again. That's all. This is designed to ensure that you know if there is a newer version. Some Inklingo downloads have been expanded and it may happen again.
The 200 days is explained in the Download Instructions,
I think if you read the download instructions it will set your mind at ease.
You can force another 200 days any time. To do that, un-check the box at the bottom of the sign-in page (to open automatically next time) and close Adobe Reader. When you open again, you will be prompted to enter your email address and password and then you will be set for another 200 days offline.
To keep up with changes in technology, new versions of the downloads may be created. You will be notified when you log in if you should download a newer version.
This is the same whether the PDF is free or paid.