Heres an example of what I meant.

I find a place with Barrier. I hit it up once. (Wand) Again. (Wand) Third time (Wand). Fourth. (No wand) So im thinking ok this place must produce three of them at least.

Im off fighting, use a few wands up, return to source, (Wand replaced). It creates a cycle of gathering that gets pretty repetitive. I use up two of the three, then fear logging off knowing that someone else might come there in the next day or so, and grab ones that should be returning.

I come to this conclusion because ive returned later to a place that I know produces wands, but nothing is returning. I hit it three or four times, still nothing. So I assume someone else is carrying the three or so wands this area produces.

Ive seen someone use a wand that I know of its location. I go there myself later and grab it when it reforms.

I have heard the rumor that you can get wand that is attuned to you or something. Probably just rumor. For me at least, its a cycle of gathering or risk loosing them.