Long distance bike rides wear out bikes. Your bike will require maintenance; if not by you, then by your LBS (local bike shop). Expect (optimistically) to get 7,000 k from a chain and 5,000 k from tyres, but this depends very much on the type of your tyres and the riding conditions.
At a minimum, before a ride you should be prepared to:
Recommended: 2 spare inner tubes, puncture repair kit, tyre levers, multi-tool, selection of cable ties and good pump capable of achieving 100 psi.
When cleaning the bike, check for damage or wear and replace any item before it expires in the middle of nowhere.