Let's say I want to use ONE tape a week for incremental. I would alternate two tapes per month so that a tape gets used every other week. I'll run a FULL every Saturday morning at 12:01am.
If I run an incremental Tues-Fri at 12:01am would the following directive work?
Volume Retention = 5
Volume Use Duration = 5
It's pretty easy. Volume will be recycled when all Jobs are past retention period and Volume itself is also past retention period. Now, do the math!