If you want to open your windows in the warmer months, you'll need to take it off. Otherwise, sunlight and normal stress can also make the tape fail eventually. For a good seal, it's probably best to re-apply them every year.
Frost King V73/9H Indoor Shrink Window Kit 42-Inch by 62-Inch, 9 sheets. Clear
From the Manufacturer
Frost King Shrink Window Kits are made for standard size windows and feature a crystal clear plastic sheet that shrinks tight and wrinkle free with any ordinary hand held hairdryer. Easily installs on metal, painted or varnished wood or vinyl clad frames with the double-face tape provided..
