I just hover or click on where multiple same size wedges appear and see what is there.
I have not done it for a while, but was first thing I tried when my disk occupancy was growing unexpectedly.
Now I regularly cull old kernels and logs, to preserve the little disk space I have.
EDIT: This thread maybe worth a look: Alternative Suggestion? (for Disk Cleaner) - #8 by zabadabadoo