This has been an interesting discussion for sure. 3 years ago I'd have been on the bandwagon that anything over 1m3 was volumetric territory, yes it still cost a little more but the savings in labour and quality of gear was well worth it. Anything more than 3m3 was a no brainer for the voley.
Fast forward to 2022 and with concrete prices where they are at, its made more than a few of us think about the cost effectiveness of mixing our own on smaller loads. I was just this week quoted £130m3 for 4m3 with 65m3 for the part load - so £650 for my 4m3. No volumetric's in the area so not a lot of choice...
Now at 4m3 its tempting to knock my own gear up, but as I want the spec its not really worth it - right on the borderline really for me.
But if I was doing kerbs.... or the access was poor, might be a different story.
Depends on area, depends on the job, but as it stands, the ability to knock your own gear up has come back around as an option. Problem with these small mixer buckets, be they auger mounted or mixing buckets in the own right is quantity. They tie up a machine on mixing duties, you still have the issue with batching correctly and they are expensive. No doubt for the right job they are essential, but for me the best compromise is either knocking up small loads on the floor or in the dumper. The machine can then scoop out of the dumper and feed the kerb brace or slab as required. Bringing another bit of kit on site for this task just doesn't add up for me, even with concrete at the price it is.
And
@Giles, I clocked that self feeding trackbarrow based concrete mixer too. Nice bit of kit no doubt, and the ability to be a traditional track barrow too, but really expensive for the problem it solved - a conclusion I think you came to as well.