I have had 4 12 month olds in care before. Diaper changes especially are a bit like an assembly line and you will change A LOT of bums in a day when they are that little (some days I changed up to 25-30 diapers). Personally I think its all in your preference and what you can handle. I LOVE babies!! I love training them young so that when they are older and still in my day home they are not horribly behaved. I also just generally love that early toddler age. When I START children in care that are 3ish I find that challenging, especially if they have developed some behaviours that are unacceptable. I would be less inclined to transition more than one older child into care than I would a younger one but thats just my preference. Lots of providers love older children and won't even accept an under 2 into care.