We tend to reset the statistics on a periodic basis. I can understand the
reasons for not doing so though. Jim had a good point about "over the
lifetime of the tape".
We reset them so that that when we do a full system save and it's taking 4
tapes we know how many bytes are on that last tape and are we getting
close to needing a fifth? If so, maybe we need to think about ordering
more tapes. It's not like the reel to reel drive we used to have that had
a bar graph of how full the tape was during the process.
And, if the statistics span a period of time when a bad drive was spewing
most of the errors we want to get those out of the system.