"It doesn't have to be hard to find, it just has to be out of reach of anyone who's actually tried. If it's in or near Sunnydale and there's a clue to be found, I'll have it by next week. If it's found its way to some other localized attractor of supernatural phenomena, it might take me a month. If someone actually managed to hide it in a hard-to-access location or erase all meaningful clues to its whereabouts, it could be longer. And if someone managed to destroy it I'll have to go with the fallback plan of figuring out how to reinvent it from scratch, which could really take a while."