Not Like It Matters
I definetly cast circles, always, because I'm a danger magnet. Stuff always attacks me, doesn't matter if it's mundane of magical.
There's something to be said to that. There are things out there that are more likely to attack a heavily shielded or warded person/object/space, on the theory that whatever is being so heavily protected has to be worth cracking the shell on to get at. By layering on protection, you're making yourself a target - some entities will assume you're hiding something from them, some might take the excessive shielding as a challenge, and others will simply want to cause trouble.
Basically: if you make yourself too obvious a target, you are always going to be attacked - whether that's being openly unguarded and incautious, or going the other way and being over-protected.
I suggest perhaps finding a middle way - one or two things that help deter the worst of it, and dealing with individual situations as they arise.