@dostovel Good question! Indeed you only want to consolidate 3 edges side by side if there’s no use for them beyond a certain detail. I think this is a great talking point to cover in the next stream, but I’ll try to answer generally here:
In the case of your batter boxes (which look awesome btw!) there’s several planar sides that don’t appear to have any additional geometric detail and in some cases are visually covered by other pieces:


Therefore the orange and blue sides are ideal candidates for “triple-edge optimization” — Let’s call it that so we both can refer to this technique quickly.
Those are the principles that govern my decision making process about optimization. But you’re the expert on this part of the backhoe, so please apply the principles accordingly!
The last thing I’ll say is that this optimization process is not completely necessary. Best case scenario is it simplifies the object as much as possible for workability and should reduce render computation / RAM usage by a fraction at least. It’s a “best practices” kind of thing. For a quick and dirty project I would skip this process.