in general, when contemplating the purchase of any field camera, I always looks for the following: (not any any particular order, and NOT specific to the Toyo Field)
hack job repairs, DiY "improvements" and creative substitutions
musty smell
mold, mildew, fungus, rust
water damage
missing knobs
missing screws
any other missing parts or parts that appear to have been substituted with non-standard parts
bent metal parts, including the shafts that the knobs turn (knobs that are wobbly when rotated)
misalignment of the sub-assemblies that comprise the bed
cracked or broken wooden parts
loose fit, overly tight fit,
skips, jumps, grinding or any other non-uniformity of motion in the focus mechanism
signs of damage, harsh use or mistreatment