I'm in the "on-time" camp when it comes to describing, for example, delivering something by the deadline. Is this the correct usage?
In a situation where you're using the phrase
However, if you're using the phrase
Finally, if you're using
When a multiword phrase is used as an adjective, then you use hyphens to join up the words. Otherwise you don’t.
Hyphen because on-time is used as an adjective modifying delivery
No hyphen because it is used as an ordinary idiomatic prepositional phrase.
Adverbial phrase: on time
This describes the punctual manner in which an action is undertaken. Examples:
My guess is that this usage is informal. Certainly it is possible to hyphenate words to convert them into adjectives. A good example is the noun cutting edge, which can be used as an adjective thus:
on time is special, as it is an adverb, but it is not uncommon to see it as an adjective thus:
I find that this sort of usage occurs mostly in marketing, especially in the delivery business. As a personal matter of taste, I would substitute on-time with other established adjectives in formal writing. Examine the following sentences:
I would prefer the second to the first for formality's sake. The third sentence, however, is perfectly fine and acceptable in all situations. It is important to recognize where on time is used as an adverb, in order to avoid incorrect hyphenation. This is a mistake I imagine is commonly made.