I will note that one of the most useful things we brought was a water purifier (it was a Steripen I got for around $70 on eBay) because that way we could get water from any source in our bottles and then purify them. If you get one of these remember to bring extra batteries (I bought some rechargeable ones and a recharger on eBay). Another key thing was the power converter because the plugs and the voltage are very different from the US. Anyway, here's our list:
What to bring:
* Reusable Water bottle (quart-size or smaller with large screw-on lid). The water from the taps in Peru is not normally potable but I’m bringing a “Steripen” water sterilizer for all of us to use to make it safe.
* Comfortable walking shoes (2 pair because of rainy season) – we’ll be doing a lot of walking and blisters can make these trips miserable.
Rain poncho / umbrella (this is the wet season in the highlands—be prepared for rain and/or mud).
* Layered clothes (include sweaters or sweatshirts) – in Cusco the average high temp is 65 and the average low is 43 (80 high / 60 low in Tacna).
* $600 – $700 each in cash or traveler’s. Include small denominations that can be used for tips to guides, waiters, hotel staff, drivers etc.). You can also use credit / debit cards (there are ATMS in the big cities).
Personal medical supplies.
* Money belt for cash and passport.
* Hat, UV protecting sunglasses, and sunscreen (the sun is much stronger at tropical latitudes).
* Reading material (for plane and bus rides).
* Electrical conversion for any appliances you bring (shaver, curling iron etc.). The outlets are the two round prongs like they have in Europe at 215 Volts.
* Camera and extra batteries.
* Toilet paper (public toilets rarely provide TP). Also don’t put paper down the toilet as it will block it. They put paper in regularly emptied receptacles near the toilets.
* Granola bars or other non-perishables for beggars (instead of cash).
* Hand sanitizer.
* Mosquito repellant (with DEET), light colored clothing, and something for itch relief
* Diarrhea medicine
* Pain meds (e.g. Ibuprofen etc.)
* Pocket knife (to peel fruits etc.)