DAX breakouts and follow-through

Been watching DAX for a bit now, and I've noticed a few times where it'll break a key resistance, run for a bit, then retrace pretty hard, sometimes even below the breakout level. It's making me cautious about chasing the initial move. For those of you trading DAX, what do you look for to confirm a breakout has real legs, or do you just factor the retracement into your initial sizing?