- Some digital copies or Ultraviolet (UV) codes do expire after a time-frame determined by the releaser.  Some expiration dates appear on the back of the video case, others do not.  So, this means you could purchase a New & Sealed copy, of an older movie and the code can already be expired, even if the case has never been opened.

- In the case of Pre-owned videos (Blu-ray & DVD) that include a digital copy (physical disk or streaming code) the code may have previously been used and some distributors set these up as “one time use codes”, so simply having the code included with the pre-owned set does not guarantee the code's use by a second or third owner. 

To further complicate this, some distributors (such as Disney) maintain a web site where you can obtain a replacement code, by providing information from the video case itself, so you can view the digital copy when the code has been previously used or is not in the set (lost).  The Disney code site is accessed by going to disneystudioshelp on the web and following the prompts to find DIGITALCOPYHELP, but again, some distributors will only do this once per video and if the previous owner has done it, it will not be avaialble for your use.

So, having said all this, my standard disclaimer for all blu-ray and DVD copies and sets that include a digital version (New & Sealed or pre-owned) is that you may or may not be able to use the digital version and all my sales are done with this caveat and are sold "as is".