Not everybody should be waking up early. I firmly believe that.
I also firmly believe that many people should be waking up earlier than they are if they want to live fuller and happier lives. Early rising is an incredible way to get a head start on the day, feel more energized, and accomplish more of the things that are important to you.
But there are some times when waking up early isn't wise - it's foolish.
1) Parents with babies waking up every night.
If you're running on 4-5 hours of sleep because your baby is still tiny and eats every few hours, the last thing you need is to lose more sleep. I was very tempted to still rise early during this stage of life, because I had an intense craving for personal time! But we need a certain number of hours of sleep if we want to function our best and maintain good health, and, quite frankly, it is dumb to ignore this! Mamas, you need to get some sleep! You don't have to wake up at 5:00 am after feeding your baby at 10:00pm, and 1:00am, and 3:00am, in order to have some personal time. There are other ways to do this!
2) When you are ill.
Sleep is a powerful tool that our bodies use to ward off and fight against infection and disease. This article from Restonic goes into some details about how this works. And, strange as it sounds, scientists have been studying fruit flies in an attempt to explain why sleep is helpful for healing, and they've found some compelling evidence to suggest that getting more sleep will strengthen the body against sickness.
If you're body is sick, just sleep in! Don't make things harder on yourself. You'll be back to normal much faster if you give your body what it needs. Be smart.
3) When you refuse to go to bed earlier.
If you simply will not put in the required effort to go to bed at an earlier hour, then waking up early, no matter how well intentioned, is going to backfire on you. You need to make a choice - do you want to wake up early, or do you want to stay up late? Because, if you want to function well, you cannot have both.
Do some people function better at later hours? I wouldn't deny the possibility!
But, I do think many people get a "second wind" at night, even though their bodies have been tired all day, and they've never tried developing healthy sleep habits. They never get enough hours of sleep, they feel tired every day and fuel up with coffee and energy drinks, and nighttime seems to be the time when adrenaline kicks in. And by this point, since we've finally finished taking care of everyone else's agenda, we get to do something we want to do.
Perhaps these people would function best on an earlier-rise, earlier-bed schedule after all. Make sure that's not you!
I believe that the most important thing is to make sure that you are taking care of yourself. Perhaps that means catching up on sleep until you regain good health, or creating an independent play time schedule for your baby so you can shower or work on that project. Or perhaps that means setting an alarm on your phone to get yourself to bed on time. Just make sure that the choice you are making is helping you.