"Back up? Don't leave home without one or pay the price..."
Near Winnipeg, CA
Last fall we went on a vacation to the British Isles. We started off in London. After a supper on the Thames we did a cruise to see the Eye and lots of real nice bridges. I was then using a D90 but I also have a D70S I keep as a spare and this time comfortably sleeping at home.
After exactly 41 frames the mirror locked up and that was it for the D90. So because I was stupid I ended up using a Panasonic LX5 for the whole trip. It's a good camera but sure not a D90.
Forget about that extra pound in your suitcase. I used to take the spare with a 24MM prime lens but got complacent. Turns out there was nothing broken, only the SQ motor lost its mind or program.
#3. "RE: Back up? Don't leave home without one or pay the price..." In response to Reply # 0
I always carry an extra body on trips. Gear always seems to fail in great locations.
I had a camera body fail on a trip to Bryce and Zion. I had a long lens fail on a trip to Grand Teton and Yellowstone. Another lens failed in England. And the latest issue was a body that was damaged while canoeing in the Okefenokee. A brand new 600 f/4 failed on a week long birding trip.
The good news - the 50 f/1.4 floats for a few seconds before it sinks. And Nikon was able to repair everything.
I have started planning lenses to have a backup as well. A 70-300 serves as an alternative to a long lens.
I've also tried to buy or rent gear while traveling. Most of the time that does not work, but I have found that Amazon can have new gear to you within a day or two. I've added a battery charger once via Amazon.