My opinion (and we ALL know what they say about opinions) on the matter is that both custodial and non custodial parents are responsible in providing for their children's needs.
Personally, I always pack a bag for Son to go to Dad's. Diapers, wipes, juice or milk, 2 extra sets of clothing, and his favorite stuffed frog. My main goal if for our Son to be as comfortable as possible when he is with his dad. And I ask that dad send back any of his clothes (including dirty) that he doesn't need.
There comes a point, I feel when it can easily get out of hand... When he's potty trained, should I send TP? Should I send bath soap? Laundry detergent? I mean, these are things I use child support to buy, so should I send them? No.
The attorney I used when going through our initial child custody case, said legally, I don't have to send anything. The percentages that are used in child support calculators are made to include the time when the NCP is to have the child/ren.
Like I said, I feel both parents are responsible for their children.
My mom was pretty naïve when she and my Dad divorced. He actually told her that out of the $900 a month he paid a month in CS, she HAD to give him $200 a month back so he could buy food for us while we were with him every other weekend. She fell for it.
My dad also made a point to humiliate my brother at the end of his weekend. He made my brother change his clothes in the car while waiting for my mom to get there. Can you imagine being 17 and having to strip nearly naked in front of God and everybody? He was very happy when he aged out of the CO.
I don't want either of my kiddos to ever feel that way. I will continue to send at least a small bag for Son unless his Dad asks me not to.
I believe after a child reaches a certain age, if the NCP doesn't keep ANYthing at their house, the child will never feel like anything more than a visitor in the NCP's home. That's how I felt, anyway. (but I was an overly emotional teen)