I don't think I read that Channel Divinity recharged over short rests. So I think just 1/ short rest would be just fine
It recharges on a short rest, so can usually use it 2-3 times per adventuring day (depending on DM/players/table/etc), which seems like enough to me. Each Paladin has two different Channel Divinity options. So by only being able to use it once, there is a choice to make.
Although I find I use Vow of Enmity (automatic advantage vs one enemy) 90% of the time more effective, except for the time I scared and caused the raging Roc to plummet off the mountain (Abjure Enemy can cause speed to reach 0).