I candle a few of my eggs every couple of days. I checked them day 5 and tossed any that were obvious that nothing was going on inside. I compared them to an egg from the store. For someone that isn't very experienced I suggest either day 9 check them look for veins. If there are veins it's good. If not toss it. Or just incubate all eggs until either they hatch or dont hatch. But be careful doing that. I've had an egg blow up on me this year (it was gross)