before each trip I plan and tweak and plan some more. But no matter what I do, every trip we go on, no matter where to, seems to fall in the neighborhood of $4,000-$5,000 anyway. So I could just save myself a lot of trouble by budgeting $5,000
For us the one thing we have very little control over is airfare, so that's first on the list.
Next comes lodging - we can adjust where we stay, or for how long to make it work. But for us, since we have to fly so far, and that's usually the biggest chunk, we figure we get more bang for our buck by staying longer but going less often. Once you've spent $1500 on airfare, might as well spend an extra $500 on a few more nights and not leave feeling like you've missed stuff and have to go back immediately. Our next trip we're using our DVC points, which certainly made this part of the budget fun to write down - $0!
Then for Disney there's park tickets to consider. Not much can be done about those either, but you can decide how many days, who has the best deal on them, and whether or not to do park-hoppers, non-expiring, etc. to adjust things a bit.
Then food: I either look at menus and average the cost of 1 sit-down and 1 cs meal per day and round up for snacks, or I allow 150 per day (family of 5, two of which are growing boys). Either way that comes out pretty similar. We could spend less on food if we brought a bunch of our own, or didn't do a sit-down each day, but dh loves fine dining, and we already do bring stuff along for a quick breakfast or maybe a snack in the room, and any more than that would feel very "un-vacationy" to me. So the food budget pretty much is what it is.
Then spending money. I try to make sure we have a couple hundred at least, but that's really the most flexible of all the expenses. Theoretically you could go on vacation and not buy a darn thing to bring home, kwim? But what works for us is to see how much we actually have, and either give the kids a budget, or give them their own portion, depending upon their age. Then they have to decide what's most important to them with the $ they've got, and they do really well with that. Last trip, the boys were old enough to have collected some birthday and extra chore money to add to what we gave them (which was $50 each - for a 14 day trip). They were really careful with it, and it was fun to see them work through the process of making their money really count). For dh and I, we pretty much decide before we go: are we getting beach towels this time? Shirts? Music CD's? then plan accordingly.
So then, when I see that it all equals somewhere around $4000 to $5000, I figure out how much of that can come from our income tax return, and how much we can spare every month to put in a special savings account or an envelope, or send to Disney - depending upon the situation, and start working on it.
We actually used to have a dedicated trip savings account - well, we still do - but now it gets used for all of our weekend trips for our boys' hockey tournaments and boy scout outings, etc, etc.. Sigh. So the real vacations are fewer and farther between than I'd like, while we spend more time in seedy hotels, campgrounds, and hockey rinks than I'd like to in the meantime lol.
