I would separate the two.. the money and the planning.
The money thing I diffuse by looking objectively and say 'is this gonna hurt me?' 'who am I spending this for? really because WE want to, or because its some expectation?' and make what I hope are realistic decisions. I tend to err on the side of 'vacation' over thrift. I am thrifty every other day of the year, so that when I do want something.. I can have it.
When I vacation, I want to be free.. so I will spend while on vacation. As long as things are reasonable.. I know I can always pay things off after the fact too. So I ensure I have the savings up front to pay for the trip itself, and I tend to have to pay for incidentals a bit after the trip. At least.. it takes some time for my accounts to normalize again
As for the planning.. if it's getting worrisome.. step back. My father is a non-stop planner - well beyond commando. He will keep analyzing over and over just to ensure he gets maximum yield, for best return on his dollar or time. So it doesn't matter if it's where we sit, what line we are in, or what we order.. he's constantly crunching. It drove my sister insane.. I could just roll with it. But it does drive people batty. I mix in the vacation mentality and say 'good enough..' and if he is with us, I force him to stand down and just accept 'defeat' and that its ok that the other line actually finished before us
For planning I've realized running to a schedule really does take away from things. It just makes things seem more like work. And when your kids get old enough to have their own desires and want to be able to make decisions on the fly.. its far more rewarding to be able to accommodate, then say 'sorry charlie, we need to be over at EPCOT in 20mins, so no we can't go and do that'. I like to think of planning as 'always having something we CAN do' instead of saying 'always having something we HAVE to do'. The kids have their best time being able to pick exactly what they want to do... even if its all over the property. I tend to tour by location first.. and then have suggestions and let the family decide from the SUGGESTIONS on what to do. Empowerment.. and less conflict. Plus, you don't need to micromanage it
I plan out things that are inflexible (hard ADRs, shows, special events), and then keep the rest flexible with a loose plan (say at the park level, or major 'to-dos'). That isn't stressful. And it gives you space.. so when you stress over having to pick between two things... often you'll find you can always come back to the 'loser' in the choice later.