You can back up the zip files, yes.  The download is what expires not the use of the samples/sounds themselves.  Personally I back up the actual installed uncompressed folder structure so it can be more "portable" but that takes up more space. For others who want to know what the 27 items that were previously unavailable to those without an AmpliTube MAX product or to those who purchased them a la carte (excluding the new X-GEAR virtual pedals from this list) are: T-Rex Moller  24.99