This is something i find myself struggling with repeatedly, ill build something myself or with my daughter, and i wont want to take it apart for either feelings towards said project or my own daughters feelings towards the set we built together, The reason im considering breaking the sets are for pieces for bigger projects.
Sets im considering breaking up:
7784 - Batman Batmobile
7592 - Buzz lightyear
Buzz isnt too big a deal, My daughters feelings about it may not be as strong as my own as she was willing to disassemble some minor projects we did using the 6177 Builders of Tomorrow set based on instructions from the website(btw, GREAT IDEA if you wanna get a kid into lego, she loves the weekly projects).
The really big deal is the Batmobile, the thing is freakishly massive, and with all those parts i wonder if i could build it again if the parts are all scattered into the main pile(not that its messy mind you, i sort by piece type or color.)
Anyway feedback would be appreciated, or if you want tell your own stories of Break up blues.