While on the subject, counters for PADL Phones and communications windchimes would be equally useful. They have a 7-adv recharge. If used within that window, not only do they not work, you lose the item.
PADL and Windchimes already have counters, that start when you use them, and last 10 advs. Apparently 10 advs is the minimum you have to wait to be certain you won't loose them.
10 turns was the current wisdom when the counters were added. Apparently, spading (where?) has determined that 7 suffices; the Wiki has changed since I last looked at it. In particular, the Wiki started claiming 7 adventures in an edit on 9 Feb 2008 by somebody named "Ruo".