[Grammar] Initial capital letters for "30-day money-back guarantee"

[Zoli]

I saw the following text with initial capital letters on a lot of websites, like so:

30-Day Money-Back Guarantee.

I'm wondering if it works with lower capitals as well:

30-day money-back guarantee.

Also, is the period necessary at the end when it is used as a caption?

 

[Rover_KE]

I saw the following text with initial capital letters on a lot of websites, like this:

30-Day Money-Back Guarantee.

I'm wondering if it works with lower-case letters as well:

30-day money-back guarantee. Yes.

Also, is the period necessary at the end when it is used as a caption?

No — it's optional.

 

[Charlie Bernstein]

Some editors would spell out Thirty-day because, when a number is the first word of a sentence, many or most grammar books and style guides advise it.

 

[Zoli]

Some editors would spell out Thirty-day because, when a number is the first word of a sentence, many or most grammar books and style guides advise it.

Thank you. Does that apply to 24/7 as well?

24/7 technical support

 

[Charlie Bernstein]

Thank you. Does that apply to 24/7 as well?

24/7 technical support

It's customary to start a sentence with a capital letter. So most editors would change it to something like "We offer 24/7 technical support" or "Technical support 24/7!"

 

[Rover_KE]

However, advertising slogans like these don't need to follow the strict rules of formal grammar.

 

[jutfrank]

However, advertising slogans like these don't need to follow the strict rules of formal grammar.

Or punctuation. Referring to the final question in the OP:

Also, is the period necessary at the end when it is used as a caption?

I'd say that the answer that Zoli wants is is a big fat no. In fact, not only is it unnecessary, it's likely to be downright inappropriate. We don't customarily use periods at the end of discontiguous phrases or sentences. I think that's what is meant by 'caption'.

(I'll repeat that it does depend on how the text is presented on the page, though, along with the kind of information presented, and to a limited extent on style.)