I've moved twice once with the packing service.
The more stuff you have the more the packers are needed. I wouldn't move again without them now.
You will need to empty drawers -the removers will not move full furniture.
Everyone also has more stuff than they think and it will take a lot longer than you think packing it up. Even with packing service you normally do a few bits yourself if you want to sort some things out.
The Packers are quicker at packing and better at getting it into fewer boxes.
They also provide all of the packing materials which are pricey. Plus I would have scrimped on helpful items like the hanging wardrobe boxes 😁.
Ours also took empty boxes away after we unpacked and reused what they could which I liked. I didn't have to guess how many and what size boxes I needed. (Plus it motivated me to unpack quickly).
On the day, if they dismantle and reassemble the house owners can focus on the more strategic side of things like directing where everything's goes. You are more likely to have a useable house with beds ready for the children that day.
If you have to clean the old property on the day you have more time and energy to do it .
I would also consider the strength and fitness of the adults helping before dismissing the packing service.
Our removals people didn't charge much of a premium Vs the basic removal. I think it's because they find the whole day goes better when they have packed.
They should get a couple of quotes and see what price difference packing makes as they might be surprised