As you read this this, I'm somewhere over the Atlantic on a red eye to Iceland.

I'll land in Reykjavik around 7 in the morning. And I'm going to be honest with you. I'll probably be asleep before we even leave the runway.

I love red eyes. I can sleep anywhere. A middle seat, a bumpy flight, a crying baby three rows back, none of it touches me. So for me, an overnight flight is a no brainer. I skip a hotel night, I land with the whole day ahead of me, and I feel fine.

But here's the thing. That's me. It might not be you.

Most people argue about red eyes like there's one right answer. One group swears they're genius. The other says they're miserable. They're both wrong.

A red eye isn't good or bad. It's a math problem.

The same flight that saves me a day and a hotel night could wreck the person next to me for three days. The trick is knowing which one you are before you book. And that comes down to two honest numbers.

The first is simple. Can you actually sleep sitting up on a plane?

Be honest here, because most people aren't. If you can sleep like me, the red eye is basically a free hotel night. You close your eyes at takeoff, you open them near landing, and you saved yourself a night's stay.

But if you toss and turn, if you need a real bed and a dark room, then you're not saving a night. You're trading a bed for a chair. And you'll pay for it the next day, probably the next few.

No shame in it. Just know which person you are.

The second number is the time difference.

A short hop, or a flight that lands in the same time zone you left, is easy. Your body barely notices. But the more zones you cross, the more the red eye piles on top of jet lag instead of getting you ahead of it.

A small gap can be a real win. A big gap, like five or six hours or more, is where even good sleepers start to struggle.

My Iceland flight is somewhere in the middle. A few hours ahead, one night in the air. Very doable for me.

So here's how you actually run it.

On one side, put the costs. A foggy arrival day. Sleep that stays a little off for two to four days. And the very real chance you land at 7am with nowhere to check in for hours.

On the other side, put the savings. A hotel night you don't pay for. Usually a cheaper fare. And a full day on the ground instead of losing one to travel.

When the savings clearly beat the costs, take the red eye. When they don't, just pay for the daytime flight and the hotel. You'll come out ahead.

Here's a simple rule you can keep. If you can't sleep on a plane and you're crossing more than three time zones, skip the red eye. It almost never pays off for you.

Now if you do take one, a few things make it a lot easier.

Grab a window seat so you have something to lean on and nobody climbing over you.

Bring the basics. A neck pillow, an eye mask, and earplugs or headphones. These are the difference between real sleep and a long night of almost sleep.

Play with the light. If you're landing in the morning, let some light in for the last stretch of the flight so your body starts to wake up on schedule.

And plan for the early landing. Arrange an early check in if you can, or find out where to store your bags. Nothing kills that free morning faster than dragging a suitcase around a city at dawn with nowhere to go.

So no, the red eye isn't good or bad. It's a calculation.

Learn your own two numbers, whether you can sleep and how far you're jumping, and the answer gets easy.

As for me? I'm closing my eyes now. Next stop, Iceland.

Keep traveling, 

Andrew

Are you a red eye lover or a red eye hater? Be honest.