Grammar fact of the day

I am apparently overly prone to hyphenating words. I knew that compound adjectives are supposed to be hyphenated. (Compound adjectives are modifiers composed of two words stuck together.) However, I wasn't sure if predicate adjectives were supposed to be hyphenated. I would certainly have a time-dependent simulation, but could I say that my simulation is time-dependent? As it turns out, I cannot grammatically say so. My problem is time dependent, as is my comprehension of the English language and its quaint usage rules.