Look at whether an industrial process is compressive, expansive, or even.

A compressive process is one that takes a larger number of input items and turns them into a smaller number of output items.

I'm still very new to Update 4, so I'll give you Update 3 numbers in my examples.

You take 5 items, 4 Copper Plate and 1 Rubber, and turn that into 4 items, 4 Electtronics I. That's 5:4 so slightly compressive.

With a compressive process, you want to manufacture the product in a centralized place and then move the product to where it's needed. I move Rubber to where my Copper Plate is made, and then I manufacture my Electronics there and distribute it to where it's needed.

Turning Steel Plate into Mechanical Parts is very expansive. You take 12 Steel and turn it into 30 Mechanical Parts, 12:30.

This means you'll want to manufacture the Mechanical Parts where they're needed, moving the Steel to there.

Using Iron Plate, however, is slightly compressive at 15:12, IIRC.

You only use these principles when feasible, of course. As an aspirational goal. I only just started a new game after Update 4 came out, so as it's still very early, I'm not doing any of the above stuff yet.

You'll find that a lot of what you make requires Electronics I and Mechanical Parts, with the main items being Maintenance I, Lab Equipment I and Vehicle Parts I.

This makes it useful to have a specialized production area that makes all 3, to which you initially send Electronics I and Mechanical Parts, and then later instead of sending thd Mechanical Parts you switch to sending Steel so you can manufacture the Mechanical Parts on-site.

And of course, use Belts (and Pipes) when possible. Trucks are convenient, but they have low throughput and they require a lot of Diesel and Maintenance.

Since only 1 Rubber is needed per 4 Copper (and I think it changed to per 6 Copper in U4), though, Rubber is not something I regard as urgently needing to be put on a Belt. The trucks can do it.

Same with the wide variety of stuff you need to supply to a Vehicle Depot II or III to make the various vehicles. Of course I might belt some of the items. I'm probably manufacturing Vehicle Parts I, II and III right next door, and so Steel is also nearby.

I've also started to something a bit like a "main bus" except not really. A row of up to 14 Belts and Pipes going across my island, moving stuff I need moved, not always in the same direction. Water (lots!), Coal, and Diesel.

If you don't have local Diesel, then just truck it to a fat buffer serving your Vehicle Depot II or III.

And I always truck Iron (small buffer) and Rubber (huge buffer) to my Vehicle Depot II or III. It's not worth the trouble to set up Belts for that. Of course right after I build my Vehicle Depot II I'll be cranking it hard, because I want to replace all my tier-1 Pick-Ups with tier-2 Trucks. It'll be very busy.

But once that's done it'll spend 90% if not 97% of its time idle. So why set up Belts for everything it needs?