here's what we say in the introduction to the Price Guide:

• condition is assumed to be excellent or near mint; not NOS or mint, but a very fine example; dial must be flawless (or near flawless, for some older models); some light wear to the case is acceptable

• rankings/values assume that the watch is on original strap or bracelet (except for the older watches that came on leather straps, few of which have survived), but does not have the original box and papers (which would command a premium).

• the models listed in the Price Guide are assumed to be ordinary production models; prototypes or extremely rare variations can be expected to sell for a premium.