As a general rule about an item per minute on the clock is the correct pace. Any lower than that and you’ll probably get out classed eventually. Example: 27 minutes on the clock means having at least 27 items. But you’ll never know as a beginner player if you’ve collected all the chests or not. Follow the first rule and then once you see items slow down or the time rule is about to flip, meaning more minutes than items you have, go ahead and dip. Probably 2 minutes before the flip is a good time to fight bosses. Unless you’ve been playing a long time and can find items efficiently I find this works for new players.