We try to save covered cups for things that need to be shaken or for cups that go along in the car. Natalie has been using open cups (we found tiny little plastic ones at IKEA in a child's dish set, along with tiny usable utensils
since she could sit up in the high chair, first with our help and then on her own; by the time she was 18 months she had it down, and could drink for bottles too w/o spilling (much
).
With Josie we were totally chicken and she had her sippy till she was THREE
and to this day she can't drink as well from a regular plain cup as well as Nat.
(Ditto bottles....)
We did find some cups with integrated straws at WalMart in the kitchen/picnic section, pretty plastic ones in bright colors, and bought about 8-10 of them; Josie still prefers to use a straw and gets really annoyed if they're all in the dishwasher (or more commonly still in her room
), so we also have a pack of straws we can use with any cup or glass if we want.
Anyway, my advice would be the earlier the better. You can start with shot glass-size cups, or small kids' cups with just a couple ounces in them at first so any spills would be limited in scope, and work up from there. Prepare for messes, encourage the kids to help in spill cleanup as part of the process (same as we often encourage them to help clean up potty-training accidents), and it'll "take" just fine, assuming no other factors that might interfere.