Most style guides—AP, IBM and Apple, for instance—make it a rule to hyphenate two or more words (up to three if you are writing for translation) preceding and modifying a noun or a noun phrase . And so we have
We run a SaaS-based solution, but not We run a SaaS based solution.
As with almost every “rule” in style and grammar, there are exceptions and disagreements. Most notably, adverbs ending in ly and followed by another modifying noun or adjective are not hyphenated:
It was a painfully bad performance, but note: It was a fast-paced performance, where fast is an adverb.
Be aware, though, that word processing programs with the compound adjective “rule” written in to their code can make mistakes. For example, MS Word would have you hyphenate the following
When a person searching for you product sees your ad and clicks it, he or she will be taken to your website-landing page.
This is not good. Why? Because landing page is a noun phrase, meaning that the two words make up one thing. So in this case website modifies the single “noun” landing page. Get it?
Still, you should be alert to the compound-adjective convention, which is a relatively new development in editorial style. At present, it is a part of “standard English” and can avoid confusion (while keeping you in the good graces of your copy editor and other lurking copy-style freaks):
Look, there’s a man eating shark!
Look, there’s a man-eating shark!
Also know that if the two modifiers follow the noun or noun phrase, they don’t usually take a hyphen:
He gazed into her limpid, sky-blue eyes.
as opposed to
He gazed into her eyes, limpid and sky blue.
Her eyes were limpid and sky blue. (Limped and sky blue are considered modifiers because were and other similar “linking verbs” like seem, appear, etc. are neither transitive nor intransitive verbs but roughly have the meaning of “equals.”)
But put two writers in a room with these sentences and they might fight about hyphenating compound adjectives for an hour—I know, how boring can it get! Each will leave thinking, “That barbarian!” One, an English literature major, would insist that there could be no confusion (and more elegance) in writing sky blue eyes. The other, a journalist, would claim sky-blue is the only choice in all cases, because AP style says so.Google+