Sippy cup transitions

Generally at what age are you transitioning kids from sippies to open cups for milk?
Most of mine have been around 18-21 mos depending on oral motor skill level and whether they spill all of the time. I have a parent of a 10 month old that was advised by a medical professional to move to open cup immediately and get off the bottle. They were told to skip sippy cup. I have never known a 10 month old to have the oral or fine motor skills to take 5-6oz in an open cup. What age do you move them to open cups? Thanks!

With group care, I don't really switch to open cups anymore. They go from bottle/sippy cup to a cup with a straw or a water bottle.

If there's only a couple one day or we are at a restaurant than they get an open cup but other than that, it's not really an option here. If we have our tea party, it's an open glass teacup and they all do fine with it but usually one gets spilled lol

As far as when they're ready though? It varies with each child and how clumsy they are at the table! haha

Don't put 5-6 oz in the cup for the 10 month old just put 1 oz ... I had a 13 month old that used an open cup .... They learn quickly

I really don't need milk all over the floor, so I'd only do a few ounces, but we'll see how it goes. This is a child who likes to throw food/drink on the floor, so I've already warned the parents that if I see that happening, then it's a cup with a lid.

All cups here are closed. So we go from bottle to take/toss cup to cups with straws. In summer when we are outside for afternoon snack I use open cups for water. If they spill or dump it no big deal

I wouldn't put that much in. Start with 1-2 ounces max. Refill as needed. Kids are skilled enough to use an open cup that young, BUT it takes adult supervision, which isn't always possible in group care.

Personally I would tell the family you will use a straw cup and will provide chances for open cup when you are able to help. Tell them to have the child master the open cup at home for a bit. Inform them that a straw cup can promote motor skill and aids in speech it is not the same as a sippy cup.