If you are referring to the expiry date of the license, then I assume you mean a temporary one, as most non-student licenses are perpetual (though we do offer lease terms). To see when a temporary (lease/trial/student) license expires, you can open the PLECS License Manager and click on "Manage license files..." and then select the installed license file.
If it's a non-permanent license, there will be a date on the FEATURE line(s). This is the license expiration date.
If it's a permanent license, the FEATURE line(s) will say "permanent".
If you are referring to the expiry date of the software maintenance service (SMS) of a perpetual license, then this information is not included in the license file, but rather in the text of the email sent with the most recent update of the license file, so you will need to look there.
