I have a friend who lives in a different country than I do. We've known each other for a couple years, and recently when we were talking, they brought up the idea of my coming to visit for their graduation. I agreed, not knowing just how long the drive was and how expensive flights were out there. I was looking into it the other night, and simply won't be able to make it work right now from a logistical standpoint in terms of cost, or timing in terms of driving because of other life conflicts. I have some reason to believe that telling them the truth, or backing out without a reason outside of my control (not just money or scheduling conflict) may mean the friendship would be over. The reason would have to be something temporary that doesn't hamper my ability to visit in the future. It'd have to be something more complex than "I'm sick" or "the weather is too harsh to travel", but not something that's super gaudy or is a threat to my life or limb. It doesn't have to be super specific.