Oh, now you tell us.
Anyway, it's thread creep time. There's an anecdote in Pete Seeger's "Incomplete Folk Singer" about how he struggled with this one song for years trying to figure out exactly when to change into the second chord. Eventually he decided that there was no second chord.
Yes, it sort of depends on how much dissonance/tension you want. "Blackjack Davey" might be done all the way thru on the tonic, or with two chords, or, if you want to show off [?!] with three.