Harriet, our house is large by most standards -- not expensive or fancy by ANY standards, LOL -- but the 90 min included pretty much "deep" cleaning -- at least 45 min doing crown molding, baseboards, corners, light fixtures/ceiling fans, under furniture -- etc.
If I do the main areas of the house like Flylady says -- just hit the middles -- it takes almost an hour.
That does NOT include 3 large rooms -- baby room, study, and guest room, plus a "Jack & Jill" bath. (I think that's what you call it -- vanity area on each side of tub/toilet area connecting ds's room -- "baby room" & guest room.)
I could hit the middles of those rooms in probably another 20-30 minutes, but except for the baby room, they are very seldom used, so I don't bother till their focus week.
Of course, sometimes I don't bother then, either.