Think of it this way, hens and pullets take approximately 26 hours to "build" an egg ready to be laid. The shell alone takes 19 hours of that time. (Which is one of the things that often takes a while for pullets to "get right" as their bodies start laying. It is not uncommon for an occasional egg to be laid without a shell when pullets first start. Takes a couple of weeks to get it all working smoothly.)
So, if she laid an egg at 0700, the next day she'd lay one around 0900, the third around 1100, the fourth around 1300, the fifth around 1500. She may or may not lay on the sixth day or the seventh because it's gotten too late to lay that day, so that "too late" egg gets laid early the morning after the skipped day. And the cycle begins again.
Not all breeds are "every day" layers. But those which are, do run into the skipped day on a regular cycle, usually within a week.