I've always bought equipment that better for the kind of photography i am interested in... i then passed on the "old" equipment. From an instamatic, to pentax spotmatic, to mamiya tlr, then mamiya 645, finally last film camera, a rolleiflex. so have really had only one camera at a time. I had to return my darkroom to a bedroom and so went all digital.
the bottom line- i've never had to decide "what to bring?" The answer would only be the camera I have!!!
p.s. i have kept the rolleiflex, and luna pro meter... you never know, right!
have fun in your travels, take a lot of pix.