A program should not be pushing and shifting a pseudo-global from hundreds of locations. Code duplication like that should be avoided by making a subroutine.
Since you naturally put all those similar subroutines close to each other in the code, you can then tell when you've got a critical mass and it has become worth it to fission the code off into a "human resources" object or module.

You don't need to refactor a hundred places. You only need to touch the subs, and they are all conveniently located in one place.

PS: Personally, I always use refs unless I know for sure that the array or hash will never be passed around. Makes variables more consistent to use, and easy to pass around.

I suppose that means that I *don't* use sigils to determine the type. Instead I use the variable name itself. Singular vs plural, noun vs adjective. As far as arrays vs hashes go, I have found that there is very little overlap between "order is important" and "needs to look up specific entries by name". On the rare occasions where both are needed, it is complex enough to be worth an object and then it supports both so there is no problem.

PPS: Hopefully there is no confusion between "you can do everything as an object" vs choking TIMTOWDI by making it "you must do everything as an object".
The latter would be bad.