Ya depends where I am too. Out here in the country it is generally OK. I never do on my 981 though, it just attracts too many haters.
Took the 986 to walmart the other afternoon and left it down. In general though it only takes seconds to put the top up.
Off topic on the way home (in my 986) I stopped at the auto parts store, this totally country lday employee came out and asked "Is dat dar one of dem nu 911s", I replied nope just a dirty old Boxster. She even noticed my zinc coated rotors, at that point she became kewl
.