This is a very hard question to answer.
How often are you running compliance archive jobs?
How much data are you archiving per job?
Little background on indexes and what to look out for.
An new index is like a full and jobs without are comparable to an incremental.
When a new index is created and followed by a job without the new index option the index is carried forward from the new index job and added to the new job. If you are running archive jobs multiple times a day and not creating indexes regularly you could be comsuming your library with mostly indexes. Double click on one of your archive jobs and go to the attempts tab. This will show you how large the index is at this point. you can find this by looking at the archive index phase. Sometimes when jobs are run so frequently without a new index you could be carrying an index that is larger than the amount of data that is secured.
Bottom line is that you need to determine how often you are running your jobs and how much data you are archiving.
There is no limitation to the amount of indexes you can browse with the super browse that I know of.
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