I suppose this is regarding Kr1stina and Wankers posts.
Agree there can be a whole lot more to packing than just loading it into the bag, much of it can be unseen :)
I said earlier that I can pack very quickly, when I say I when I am working this is my husband and I. If it's a week long
break, a few days before we will casually talk about what we need, gradually collect entertainment depending on the break, if that is tech media or actual books, cards and drawing stuff. We will both pull out tablets and chargers as we come across them. It doesn't take long or much thought because we have designated dumping areas for such items. We both pack our own stuff, family toiletries are generic and easy.
Then we each get assigned a child, the child may pack and choose their own clothes and extras but the assigned parent does the line management and checks. This also includes what they want to read, have they actually downloaded the Google Playlists they have set up. Obviously the clothes are much easier if at the start of Spring or Autumn a parent has gone through their clothes and thought about what they have for the coming colder and warmer temps and what should be stocked up on in the next size up. All part of future packing.
But yeah, overall easy planning and packing equally(ish) shared.
I haven't worked many school summer holidays for the last 16 years so yes all that thinking does come down to me then. We don't do flying to AI holidays for the summer hols and so more thought is needed. Once again I am disappearing for the entire 6 weeks with the kids and my husband joining us later so I am not expecting him to do hardly any of the thinking 
He still has done a fair bit of media sourcing for us all, taken charge of the phone and tablet for my youngest, planned and picked up various medicines.
Yes, I am the one that has been packing for a month and been working through the kayaks and snorkels. I have been packing for multi destination trips for years and have learnt where I need stuff. It is all long term planning with no drama affair. I have made collections of all the gear recently. Finally I could get the car cleaned yesterday. So today I could make sure that:
Glove compartment = small bag with half used toilet roll, antiseptic wipes, antiseptic handcleaner ( for those aires, people will know if they have experienced). Torch. Spare bags for rubbish. Upholstery wipes for spills or sick. Spare travel sickness tablets.
Tiny odd storage near driver = emergency pain killers, anti acids, hair bands, euro change .
Under passenger seat = old spare of glasses for all of us plus glasses repair kit.
By each child door = emergency vest.
In each rear pocket = sick bags, clip on sunglasses, emergency microfibre mopping up cloth.
I take my time and methodical, slow and double check x 3. Mainly because my short term memory is shit.
If somone called me up and said we're sending a taxi in the next hour you need to be in Zaragoza for a business meeting, or Berlin for a weekend with friends, I could do it nomprobs but family holiday where people may need certain things, yeah thought was put in at some stage.