License Clarification.

[al3x]

I would like to know if rescue.iso created with a one-year license also expires after a year, or is that iso valid forever?

There is no buyable one-year license, licenses are perpetual. See here for all available buying options.
If you buy a license this will be valid forever, for both the installed version and also created WinPE rescue media.

Giveaway licenses on the other hand expire after one year which means the installed version as well as created WinPE rescue media will fall back to the free version.