I think a ten-step scale is asking for subjective,
indecisive opinions and will spawn arguments.
What, really, is the difference
between "AS NEW" and "EXCELLENT?"

There are a lot of smart people here;
perhaps we can create a six-step scale
with solidly-defined benchmarks that
make the difference between
"Excellent" and "Good" easy to understand.
We just need to chew on it a bit.
One way to make fewer steps but with better
definition is to make it "dual-scale"
with specifing phrase, spliting the five steps
into two scales, one for working equipment and one
for non-working equipment.

For instance:
An R-390 in average surplus condition working fine:
Condition "GOOD/WORKING"
The vast majority of gear would fit here.

An R-390 in average surplus condition,
working except for the top band:
Condition "GOOD/WORKING less top band"

A KWM-1 without a scratch that has been in storage
for twenty years- you don't want to recap it and
don't want to turn it on for fear of frying things:
Condition "EXCELLENT/NOT WORKING untested due to long storage"

A Hallicrafters S-38 with rusty chassis, scratched-up face
and only buzzes with that "roasty smell:"
Condition "POOR/NOT WORKING"

If a person is interested, he'll write for details.

That would give us two scales, something like this:

1. NEW IN BOX/SEALED or /UNSEALED
2. EXCELLENT/WORKING or /NOT WORKING
3. GOOD/WORKING or /NOT WORKING
4. FAIR/WORKING or /NOT WORKING
5. POOR/WORKING or /NOT WORKING
6. PARTER (not working by definition)

plus a specifying phrase if needed.
With a little head-scratching, we can
develop benchmarks for these that will take
most of the guess-work and opinion out of it.

Just MHO,
73 Dave AB5S