Descriptive grammarians would say the adjective 'long-lasting' can be written without the hyphen, while those of us who prescriptively insist on a little more consistency in grammatical logic would say that it can't, or at least shouldn't.

I don't think it matters if it appears before a noun or after a verb, though there is theoretically more room for misunderstanding if it's left unhyphenated before the noun.

Compare "two legged mammals" against "two-legged mammals"

Descriptive grammarians would say the adjective 'long-lasting' can be written without the hyphen, while those of us who prescriptively insist on a little more consistency in grammatical logic would say that it can't, or at least shouldn't.

I don't think it matters whether it appears before a noun or after a verb, though there is theoretically more room for misunderstanding if it's left unhyphenated before the noun.

Compare "two legged mammals" against "two-legged mammals"