From another question I understand that "1-day offer" is the way to go, but if I rephrase it a little bit:
The offer will last for 1 day
The offer will last for 2 days
Which one needs to be hyphenated if at all?
From another question I understand that "1-day offer" is the way to go, but if I rephrase it a little bit:
The offer will last for 1 day
The offer will last for 2 days
Which one needs to be hyphenated if at all?
No hyphenation is needed in these cases; this is just 'normal' use of a cardinal number. You can compare this with something like "I see two apples."
Note that I have replaced "2" with "two". As noted in the comments, in most cases, it's customary to write out small numbers in full.
And for future reference - are there any cases where using "1 day" over "one day" is more favorable?
– Laliophobic Jan 30 '17 at 07:50