It really depends... but what the last few guys said, and the early guys is deadon.
Leadership has different standards than recruit division, mind you, esp since the room layouts are different, although some recruit courses sometimes are in Blue due to space issues...
Anyway; the civvy "lockup" (rarely locked, really) was a favourite storage place for all manner of things... we had already been issued a ton of military kit at Prep Year, and often in crazy amounts, so we had doubles of some things, and everything was already marked.
Honestly, the best thing I could ever suggest you get is a hand-held sewing machine. I remember seeing one on The Shopping Channel two weeks before I left, and never bought it, thinking, Who needs that? it was like 30$. Well, of course we arrive in St Jean, and find out you have to mark all your kit.... by hand sewing...! We hit Sears on the weekend and still couldnt find a handheld...
Anyway, everyone generally had a second set of stuff.... the only thing I used was the shampoo I think, and that stopped about midway down, and I bought another one... the razor can be a cheapie, etc.
and yes, course staff really have heard/seen/done it all.. and many of them are on here telling y ou so