I ignore all eggs, mine and shipped. I candle a couple of times before lockdown. What works for some won't work for others for sure. Staggered hatches are about to make my eyes cross. I keep planning on the last set I will do and then, have to do more... Stacked eggs I have not tried but I use the auto turner so don't think that would work.
once you know your bator.. and how it reacts with your environment year round (basically once you find out what works for you).. you don't need to candle unless you're working with waterfowl, parrots or turkeys..
then mainly it's to check for internal pips
but with shipped eggs you have a lot of unknowns.. thickness of shell.. porosity .. and so on.. so I make sure I candle them to check that .. plus to look for hairline cracks!
with everyone though (especially newbies to incubation) I always suggest monitoring eggs.. it's the best way for them to learn how things work for them
heck.. 9 times out of 10 I forget when hatch date is.. just had chicks hatching out the other day when I went to turn the darn things.. plus I do so many batches of stacked eggs and staggered hatches it's easy to lose track of who is hatching when![]()