When to potty train?

I had a really interesting conversation with another mother last week. As I've mentioned I am currently running a home daycare. Two of the children I care for have parents who are from Eastern Europe. One of the children is a boy who turned two at the end of January. He came to me completely potty trained. I have to admit that I was both skeptical and impressed when his mother originally told me that. But it was true. He knew when he needed to go, had no accidents and only wore a diaper for nap time and for outings.
The little girl I care for won't be two until July. One of the things her mother was upset about at her last daycare was that she had sent her daughter to that daycare potty trained and that daycare worker decided it was too much work to keep her on the potty so kept her in diapers, never taking her to the potty. Again, I was a bit skeptical, but I figured if her mom is training her at home, I will continue on in the daycare and take her to the potty here. Again, I've been impressed. She will pee on the potty (not all the time, but at least once every day).
Back to last week's conversation. The 2 year old boy's mom asked me if any of my boys had potty regression. Mine didn't but they were much later to train. My oldest was 3 1/2 before he was completely trained and my younger son had just turned 3. This little guy was starting to regress at home. I hadn't yet seen it at the daycare, but sure enough a few days later he stopped letting me know when he had to go potty and started having accidents. This mom said that she thought regression was a common thing, that other mothers she knew experienced it.
I asked her about the early to train idea and what I discovered was really interesting. She told me that back home (Romania), children start training as soon as they can sit (6-7 months old). Most children wear cloth diapers and their parents just keep them close and keep sitting them on the potty to learn association. She said that she found it frustrating talking with her mother back home and having her mom get on her case for not starting this little guy on the potty when he started sitting. She said that she couldn't find a small potty here, as most potties are designed for 18 months plus. It was only when her mother came to stay with them for 6 months that he started to train. (at about 18 months old).
This is what is referred to as Natural Elimination (NE). NE is common practice throughout the world. Keeping your children close to you. Learning their rhythms and associating the potty at a very early age. Actress Miyam Bialik is a North American example of a mother who used this technique. Both her boys potty trained early on and were in underpants at about 15/16 months.
I can see where the idea has merit and I think it takes a lot of dedication to follow through with it. You have to be able to devise a way to communicate the need to use a potty very early on. Some parents are quite successful at introducing a sign for this.
The North American mindset for potty training is quite different than this. For me, the idea of training a child to go to the potty means a number of different factors, it isn't just the ability to pee on the potty. (As one mom who is training her daughter early shared, "sometimes you catch it, sometimes you don't"). It's more of a complete ability. Does the child have the ability to independently use the potty? Can they communicate their need? Can they undress/dress themselves? Can they wipe? Can they 'hold it'? When all of those things are happening at once, I consider them to be fully trained.
I don't know that their is a perfect age or perfect way for this to happen. If you are someone who believes in the holistic NE method and you have the time to do it, then good on you. I'm not.
The little girl I care for is a 'hit and miss' kind of potty-ing. She doesn't communicate to me any need to go. Sure she'll sit on the potty and sometimes something happens. But sometimes it is a trickle, which makes me wonder if we just got lucky. She doesn't appear to be bothered in a wet diaper. She doesn't seem to have the ability to 'hold it'. It seems like sitting her on the potty is more of an extra step in changing her diaper. I take her at regular intervals and I will continue to do so as that's what her mother wants.
I think the little guy I care for really and truly was trained by age 2, but is experiencing a regression, for whatever reason. But again, he had a very dedicated care giver to work with him young (his grandmother in this case).
For my daughter (15 months), I think I'll wait a little longer. When she shows me interest and capability, then we'll start. It's not a priority for me to train my kids young. It's more a priority for me to know that when they are trained, they are trained completely to be independent at it. In any case, I'm the one who has to deal with the diapers.