In Britain, whilst it is 'de rigeur' in Universities to hyphenate adjectival phrases, such as 'a time-honoured custom', 'a quick-witted response', 'an egg-headed professor' etc., there seems to me no such requirement for adjectival predicates, though I tend to do so on an ad hoc basis if it feels right.

In Britain, whilst it is 'de rigeur' in Universities to hyphenate adjectival phrases, such as 'a time-honoured custom', 'a quick-witted response', 'an egg-headed professor' etc., there seems to me no such requirement for adjectival predicates, though I tend to do so on an ad hoc basis if it feels right.I would say, if in doubt hyphenate. I don't think one would be criticised for too much hyphenation in this way. At least that seems to be the case in the UK.

In Britain it is 'de rigeur' in Universities' humanities courses to hyphenate adjectival phrases, such as 'a time-honoured custom', 'a quick-witted response', 'an egg-headed professor' etc. In my sixties I took an undergraduate degree in history and was surprised at the extent to which my tutors insisted upon this.

In Britain, whilst it is 'de rigeur' in Universities to hyphenate adjectival phrases, such as 'a time-honoured custom', 'a quick-witted response', 'an egg-headed professor' etc., there seems to me no such requirement for adjectival predicates, though I tend to do so on an ad hoc basis if it feels right.