It was 2012 and I had just booked a flight from Ho Chi Minh City to Kathmandu for the wrong day. I would be flying with AirAsia, who, I assumed, like practically every other airline I've encountered, would allow me to change my flight free of charge if it was within 24 hours.
Not the case.
Instead, I was out almost $50 to change my flight to the next day within twenty minutes of booking it. I learnt my lesson that day and am now cautious with who I fly with. Fortunately, with four more years of full-time travel under my belt since then, I have yet to pay for a change fee.
Here's how you can avoid paying them.
Double Check the Booking Before Confirming
It sounds like common sense, but it's happened to me and many of my friends: you're paying attention as you go through the booking process and hit confirm without checking your details are correct. Make 100% sure that the date is correct, the time is correct (especially if you're flying at around midnight -- friends have regularly booked a 00.30 flight and turned up at the airport 24 hours after their flight was supposed to leave!)
Try to Change Your Flight Within 24 Hours
In the case of my flight to Nepal, I was still charged for changing within 24 hours, but this isn't the case for most airlines -- especially if they're not budget airlines. If you're going to be flying domestically, know that in the United States, airlines have to allow you to cancel free of charge within 24 hours of booking the flight, so if you're having a panic about the flights you just booked, then is the time to change them!
Buy a Flexible Ticket
It's possible to buy a flexible ticket when you book your flight, which for around $50 more will allow you to change your flight free of charge if you need to. It's worth doing this if you're not 100% sure of your travel dates but want to lock in a particular fare, or if you know plans could potentially change in the future. It's not an extra expense and may end up saving you a small fortune if you do have to change your plans.
See if You Can Get Yourself on an Earlier or Later Flight
It's typically far pricier to change the date of a flight rather than the time. If you can't make a flight for whatever reason, but could take one 12 hours later on the same day, then get that flight rather than one for the following day.
Get Travel Insurance
I always recommend traveling with travel insurance, and if you happen to be with a good provider on a decent plan, your trip cancellation is likely to be covered by them. Yet another reason to have travel insurance!
Pull a No-Show
Yes, it's not particularly ethical, but if you do some research online, the airline you're flying with may charge more for you to change your flight than for you to not turn up at all. Try looking for alternative flights that better suit you, in case there are any that are less than the change fee.
Plus: if you don't turn up, you're entitled to have the taxes and fees you've paid on the flight refunded.