It does seem today we simply follow the regulations, where when I was an apprentice we used what we considered as common sense. There have been a few changes which may seem niggling, however to my mind go down hill, including names, I always considered a spur to be a branch from the main supply using a smaller cable, there was no such thing as a fused spur, that was called a radial, as any other supply from a overload protection device.
As to volt drop across a fuse, I have only once noted the volt drop across a fuse, some one had fitted a RCBO with 4.7kA limit supplying a charger for a radio in the main control box for a crane, however the PSSC was above that limit, so it was to be replaced with a fuse, but on fitting the fuse found the resistance of the fuse actually brought down the PSSC to within limits.
I understand two many fuses can cause too much volt drop with items like freezers, they have a overload device to trip out should the pressure be too high on a restart, and so are vulnerable to volt drop, however I can't think of any other device which is so vulnerable to volt drop.
I had a problem getting a re-wire, I had very limited time, too short to do a DIY, and only found 2 firms able to do the work one twice the price to other, and I took the cheaper, they put one guy full time on the job with a mate, however he over ran on time, so job was flooded on the last day, to finish it, and most the faults it seemed happened on that last day. However it was ready for mother to move back in, so all in all it was the right choose.