Well, I bought this 1957 home a few months ago. I don't really like old houses but it's just for the kids (good schools).
So we moved in.
There used to be rats infestation in this house but no no more. I hired an exterminator to seal all the entry points and have traps.
There were rats on the attic and crawlspace too. So I hired the insulation companies to remove batt insulation in the attic. For now I have no insulation for easier clean-up, sealing and some electrical work. The insulation guys told me that they have used vacuum to suck everything out already. But when they are gone I found out that there were still locations with rat poo here and there. After they have left, I must have spent like 10 hours up there in the attic, wearing facemasks and coverups to remove the stuffs that they haven't removed: lotta wood pieces here and there. Nails, bricks, etc. Now my attic is pretty clean.

Only at this point did I feel comfortable to let the insulation guys coming back to put on insulation.
The same is for the crawlspace. I have crawled down there picking up woods, old pipes, hundreds ft of old communication/phone wirings, bricks, tons of nails, coke cans, tools, paper, light bulbs etc.. I must have removed 100 lbs of stuffs from the crawl space. And I am not 100% done yet.
My wife kept complaining that I spent too much time cleaning up the attic and crawl space. For her, out of sight, out of mind. She doesn't really care. But for me, just a thought of having trash in those hidden places irritates me a lot and I just have to do it. Am I being too obsessive? do you guys clean up the attics/crawlspaces and you really don't care?