Single, hyphenated, or double?

During the final proofreading of Notes from the Nineties, I’m finding small amusements in MS Word…which seems to be contradicting previous versions of spellcheckers.

Or is that spell-checkers? Spell checkers?
I’ve always had a habit of using single words where others prefer double or hyphenated words. To me, reproducing spoken language makes dialog in particular (of course) and prose sound more natural. Now that the automated spellchecker (spell-…spell…) is suggesting single words over other options, I’m finding a number of inconsistencies.

For example, the program suggests “flowerbed” (OK…) but “death bed” (um…why?). Gravestone is one word, but grave marker is two…but they mean the same thing (don’t they?). Rune stone is two words (but it’s only one object, like a gravestone…). Huh?

Which would you prefer? Single word? Double? Hyphens?

Below I’ve written the original form of 2-word nouns and adjectives in my stories (most dating from, you guessed it, the ‘90s) in the order in which they appear. Try to guess which ones were flagged by Word as “misspelled.” (Note: I changed many to single words…which ones would you change?)

camp fire
deathbed
flower bed
roommate
stop light
firebrand
southbound
off season
ear-splitting
firepit
stone walls
newly-graveled
eighteen wheeler
dimly-lit
sidepocket
cut-outs
cubby-hole
wrist watch
name tag
gumline
militia men
apple sauce
sing-song
toll booth
fast forward
day-long
door frame
head-first