I put all the eggs in one container and just check on them throughout the day. The container sits on the kitchen counter, so I just take a peek at it each time I'm over there. My kids are also good at spotting new caterpillars. Also, sometimes I put the eggs into another container with fresh leaves when I see that dark spot on top (meaning it will soon hatch). Once I woke up to find several had hatched overnight. They'd crawled up the side of the container and luckily left the other eggs alone. So far, no casualties!
As another tip (which is something I read here last year and decided to implement this year) is to use a hole punch to easily cut out the part of the leaf with the egg on it. I then line up all the little leaf circles on a paper towel in the bottom of a plastic container. It's easy to see and keep track of the eggs, and the rest of the leaf gets fed to my other cats.
Thanks to whoever suggested that here! It's my new favorite rearing trick!