I report a lot mainly because of the OP here. You see, we had this thing going where we wanted to report more than each other and couldn't report the same thing, luckily, PC has/had a lot of rule breakers so it's pretty easy to find things to report just from looking over sections I might be interested in posting in.
I mainly report in CBC (being probably the forum I check the most other than B/W), and everywhere else it just depends whether I see it in New Posts or if I see it from reading through the rest of the sections.
Since I have access to modcp, I never report something if someone else has reported it (I have the reports button on bookmarks so I can click and instantly get there, lol). I generally write detailed reports (at least longer than a few words, other than the "belongs in...") and always use links when appropriate since I figure the mod in question might someday find a link to where something should go to be useful.
Oh yes, and I always check if my reports are done, I check modcp a lot per day just to see if they're done or if someone questions it and I need to comment, and if they're closed, head to the thread, if there's nothing, literally go back pages in closed reports just to see if there's a comment so I know what that mod in particular prefers/would do in the future. But yeah I'll report all sorts of things and I generally have a grasp of what's allowed/what isn't in other sections (except emulation/writing/etc) so I can report in most places.
Also, as for me and how I handle reports, I figure it's worth mentioning that I use the little "Reports: 1" as a way to show me something is wrong in Black and White, and if I can't find it, to actually go see the report in particular and go from there. But yeah I generally do things first without checking reports just cause it's easier that way for me I guess. BUT, sometimes, reports are useful, so they can be a good thing too. :3
@Insomniac: we generally don't tell people who reported their posts since there's not a need and I can't really think of a case when that has occurred.