How long should I continue to try to get my lo interested in one type of sippy cup before switching to a different one? I have tried giving him a sippy every day for the last few weeks, but he hasn't even figured out that there is anything in it. He has never actually sucked on it, just chews it. I am currently giving him the Avent training cup. Should I try a different kind or is this par for the course? I can't remember what it was like with my oldest, but then again, he was a much easier baby than my youngest.