How to monitor HTCondor pool usage
Known to work with HTCondor version: 7.0
How to see accumulated usage per user
condor_userprio -usage -allusers
If you want to track usage over time, one way is to save the results from the above command periodically (e.g. every day) and then build reports from this historical data. Some working scripts that do this (used on the Wisconsin GLOW pool) may be found here.
The CondorView tool may be used to interactively view historical statistics for a queue.