If I have a destination wedding on a Saturday, I always fly out on Wednesday or Thursday. The reason for doing this is that if my flight was delayed or canceled, I could switch airlines and still get there on Friday at the latest. It would not be prudent to fly out on Friday for a Saturday wedding, as you would be running the risk of a flight being delayed or canceled, and then you might miss the wedding, or be late to the wedding. And, I would never do that to my clients.
So, the minimum amount of time I would be on site for the wedding would be 4-5days. This allows enough time to get to the location (even if my flight is delayed), to rest up from the flight (oftentimes the flight can be anywhere from 4 hours to 16 hours, and traveling can be stressful and tiring), to scout out the best locations for portraits, to get to know the families so they are comfortable with me on the wedding day, to shoot the rehearsal dinner, and to prepare for the big day of the wedding, etc. And, on the day after the wedding I can do a TTD session for clients that want to take advantage of that option.
Hope this helps.
Best wishes,
Tod