Smyth notes in 2455 N. that after verbs of fearing, the affirmative statement is the thing
being dreaded and so the regular construction after πρίν is acc. w. inf.
But the example he gives from one of Euripides' fragments shows a redundant πρίν,
at least it seems so from his translation. Is this common? Where might I find a reference to it?
δέδοικα μὴ πρὶν πόνοις ὑπερβάλῃ με γῆρας πρὶν σὰν χαρίεσσαν προσιδεῖν ὥραν.
I fear lest old age overcome me with its troubles before I live to behold thy gracious beauty.