Artoomis said:
It's pretty clear. The staff may be MANY things before the charges are all used up, but, after that, it gets to remain a +2 quarterstaff - not a "Staff of Power" any longer.
Actually, the description
doesn't say that it isn't a Staff of Power any longer (though the +2 Luck bonus
does depend on it being a Staff of Power). Nor does the general description of staves say that a staff with no charges is anything other than what it was while it still had charges (the way, again, that the general description of wands
does). That's my point. It's just out of charges. A staff that has no abilities other than to use charges to cast spells doesn't do a whole lot once the charges are used up. But the ones that do have abilities not based on charges seem to retain their usefulness. E.g. a Staff of Fire that runs out of charges is still a Staff of Fire; it just isn't really good for much. On the other hand, an uncharged Staff of Woodlands still retains the qualities that weren't charge-dependent.
There is only one ability of a Staff of Power that explicitly remains after the charges are gone (besides, obviously, the ones on which charges must be spent): +2 enhancement bonus on the quarterstaff. Likewise, there is only one ability that explicitly
doesn't remain after the staff is out of charges: Retributive Strike (I suppose the Retributive Strike could be considered "charge-dependent," but only by virtue of the fact that it disappears once the charges are gone). Of the abilities undescribed, I count two that do not require spending charges: +2 Luck bonus to saves and AC, and the nebulous "smite."