David:
I'm pretty much in the "keep those extra sprues in my kit, Thank You" and "companies do better by making one sprue with parts for both current kits and future versions" school.
I logic things thusly: The actual styrene used in the kit is pretty cheap. A company has a huge investment in engineering each new sprue and set of molds. Making one sprue and its molds serve for several kits is efficient and cost-effective.
If a company anticipates that it MAY release some future version of a vehicle- seems that it would make a great deal of sense to make a sprue with parts to cover into those future kits. The alternatives are to either engineer separate specific sprues and molds for each kit, or clip sprues so that the extra parts are removed and not passed on in the "wrong" kits.
I think that engineering the separate sprues is a sure-fire way to raise production costs of kits. You are axiomatically removing or reducing manufacturing efficiency and increasing the number of production lines or operations to "the maximal extent possible" by doing this- it ensures that you need to do additional moldings for every different kit produced.
There are more than one case in Dragon kits where a "new" kit comes out with almost no new engineering of sprues or molds- the recent Cyber Hobby Sd.Kfz. 250/10? with 3.7cm Pak 36/37 is a good example of this. They combined sprues from several extant old kits and printed a new box. That's pretty efficient!
And about as cheap as producing a "new" kit can get! In contrast, going the "create all new sprues for each new kit" is the maximally expensive route.
From this, I would conclude that kits would be more expensive if the companies went this route.
That other alternative- clipping parts from sprues- also raises costs per kit over simply including the whole sprue even if only a couple of parts will be used. Clipping adds production complexity by adding handling steps. This means both more labour tasks and time, and increased chances of labour error. This means that a kit made up of many trimmed and clipped sprues will be both more complex to prep and pack, cost more in labour, and be more prone to problems of missing sprues and damaged parts resulting from folks clipping stuff. In addition, the company actually needs to dispose of the clipped-off parts- a waste cost. This alternative raises costs, and may well also reduce consumer perception of kit quality. This also increases the need for a support and parts-replacement service... yet more cost per kit.
Way I see it, either route other than "include the spare parts" is more costly, and should logically lead to more expensive kits.
Just my opinion, of course!
Cheers!
Bob
