We mainly organize off-road tours, so depending on the kind of tour a MTB or Gravel bike is necessary. As we always say, it is not necessary a last generation bike to ride one of our tour. Of course the bicycle must work perfectly in all its part: brakes, gear, suspension. this will allow you to fully enjoy the tour. Avoid to leave with a new and  never used before saddle.
Ten days before departure is best to make a complete check with your bike mechanic.