Exercising magnetic tapes

I am currently writing a preservation plan for our audio/visual
collection. I've read in the literature that audio tapes and videotapes
should be "exercised" by playing and then rewinding. However, I'm not
sure how often this should be done. The range I'm seeing in the
literature is between 6 months and 3.5 years.

Does anyone have a schedule for "exercising" tapes? What is an
acceptable interval? (6 months is not very practical) What about motion
picture film? Any help would be greatly appreciated.

Michele Zeccardi
Niels Bohr Library
American Institute of Physics

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                  Conservation DistList Instance 8:16
                 Distributed: Thursday, August 25, 1994
                        Message Id: cdl-8-16-014
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