When you are writing a sentence that contains hyphenated adjectives with the same last word, delete all the repeated words except for the last one; however, keep the hyphens to indicate a connection to the last word. This is the rule of the suspended hyphen.
Long-term or short-term loan
Open-door and closed-door policies
Two-door or four-door car
A one-week to two-week vacation
Long- or short-term loan
Open- and closed-door policies
Two- or four-door car
A one- to two-week vacation
Note: Use one space after a suspended hyphen unless a comma is needed.
3-, 6-, and 9-month updates
The rule of the suspended hyphen also works with compound words with a common element, e.g., daytime and nighttime.
Please provide your day- and nighttime phone numbers.
This rule is why in a previous post I answered a BizWritingTip reader’s question as follows: “If the writer does not explain him – or herself clearly, readers will often get incorrect information.”
And, yes, I do agree that it is better to make the noun plural: “If writers do not explain themselves clearly, readers will often get incorrect information.”
However, writers do need to have options.