@ovidius,
Quote:I'm not sure what the rule is here.
In spite of some experience in the field Ovi I'm never quite sure what the rule is, or even if there always is one
It seems to me that the miles don't fall in quite the same category as the distances. A hyphen hooks words together (esp where they modify), so in the case of "a group of twenty- to thirty-year-olds," If you omit the first or second hyphen for instance you get twenty to thirty one-year-olds
…whereas if you omit the last you get something puzzling: An unspecified number of oldsters of uncertain age who might, for instance, have been pursuing a notion or political idea for some twenty to thirty years
In the case of distance "six-to-eight miles" seems right because as you said, "six-to-eight" is a unit modifying "miles." However for some reason someone else will probably explain below, in this instance collo wouldn't use hyphens at all per Rag's excellent posting above. However in
Quote:Correct: "The event was geared for 6-to-8-mile-runners."
I'm not sure I'd use that last hyphen. Dunno why, collo mebbe