II do home childcare and have usually had great parents. But I can sympathize with a lot of the peeves dcp have mentioned so far.
The childcare provider/parent relationship seems to work best ime when parents and providers have similar philosophies. I'm kind of crunchy and have learned to be upfront (even ostentatious) about that in interviews. If you don't like me putting your infant in my baby sling or feeding a variety of healthy food choices that might be unfamiliar to your toddler, my home won't be a good fit for either of us.
I feel it is part of my job to be supportive of parents, but I have felt resentful of parents who do physical discipline (spanking) at home, because I believe spanking is wrong. I've had kids seriously misbehave (hurt another child) and beg me not to tell daddy because "he'll give me a licking"

. If I have families telling me in the initial interview to spank their kids for misbehavior, I know it is not going to work out.
Some families need really long childcare hours because they have insane work hours, shiftwork, single parents etc. -- that is tragic, a sign of a society that is unfriendly to families, but I don't feel peevish about it if I take families like this on. I have gotten on very well with sahms who need a day or two a week for a break -- often there is no family in town and dh works out of town or very long hours.
But I am AP enough to believe that it is important to make spending time with your children a priority as much as you can.
I looked after one family on a temporary basis in which mom and dad dropped off the moment I opened and came home 2 hours before I closed but NEVER picked up the children early. The children were in my care for 11 hours a day 5 days a week, because "we pay for the hours, so we use them". I was also told not to let the children nap because then they wouldn't be ready for bed at 7:30 pm. Sleep deprivation is a form of torture, and I couldn't bear doing that to a 2 year old

The children were lovely, but when the parents called me looking for full-time care, I never had the space.

It wasn't that the long hours were such a lot of work, though they were, but I just couldn't fathom a family having the option of spending more than an hour of waking time with their kids on weekdays and not *wanting* to do so.
I really try to encourage and support extended breastfeeding, etc. I think it makes children happier and healthier and that makes my job easier, overall, even if I do have to rock a baby to sleep now and then. But my own dd was the nurse to sleep sort, and her dcp had the worst time getting her to nap, so if I have a difficult napper, I figure it's karma.
Maybe turning it around and asking what dcp like most about parents would be appropriate?
The best thing any parent could do for me is to have a smile for me in the morning and a kind word for any of my children who happen to be around at pickup and dropoff. The dhc and their parents are like extended family to my children and I so value parents who seem to feel the same way. Honestly, I will go a long way out of my way for any family who seems to truly respect me and what I do and who shows kindness to my own children.
I treasure cards and notes from parents that express genuine appreciation for the care I give their children.
Also , checking with me about bringing outside food in can be very important. I might not want a child to bring a box of dunkaroos to share for morning snack....even if I don't have a child in care with severe allergies, as I have had in the past.
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