'They were up talking until all hours' (until very late at night) 'She's been working all hours'. (night and day) 'Isn't it about time we got a new car.' (we should get a new car soon) 'It's about time you arrived!' ( you should have been here earlier!)

Example: I've been up to all hours correcting these essays. It's about time people stopped posting their homework on italki and did it themselves.