AA 1.5 doesn't really need it, because the saving protocol is different. 2.0 and later make you save everything before you start, while 1.5 and earlier asks you what to save at the end of the session. As a result, 2.0/3.0 saves everything in sight and you end up with all the alternate takes, punch ins and whatnot and HUGE files associated with any given session. There are two ways to get rid of all the extraneous stuff: one is to tell AA to delete unused clips when you open a session, and the other is to use the utility (which I have, by the way). Either one is more or less intrusive in the workflow (the utility -- at least, the 2.0 version -- requires you to open it separately for each session).
I was able to use a 40GB audio drive with 1.5, but when I went to 2.0 I installed a 400GB because I was constantly running out of space. As I said, I have regressed back to 1.5 (compatibility with earlier versions of AA and CEP, more familiar mixdown procedure, easier -- for me -- saving protocol) and it works fine.