While CD-R media is tough, it is not unbreakable. The tracks on a CD are 1.6 microns apart, so dust, dirt, fingerprints, etc. can reduce reliability. Make sure to handle these disks like an audio CD - by the edges only and with clean hands. Store CD's in their jewel boxes or keep in the CD-R caddy provided. Avoid exposure to bright sunlight to avoid warping. For maximum data life manufacturers recommend storage in the dark, with less than 40% relative humidity, and the temperature less that 25 C.