If you do pediatric testing, you might want to keep/store them until age 18. Why not burn the study/video to a CD or DVD and tape them inside the patient chart (using standard white, labeled, CD envelopes)?
Also, If you ever have any "problem" patients (parents), it could also be used as "documentation" in potential future liability. It would be more cost effective than possibly a long drawn out court case. (Luckily, that hasn’t been a problem in any of the centers I’ve worked in over the past 20 years, but it is a less expensive safeguard).