The choice of whether to replace might depend on the length of the tour and the availability of parts along the way. Personally, on a longish tour I wouldn't find it to be too big a deal to lace on a new rim assuming one was available and on a shortish tour I figure that the rim would be very unlikely to fail completely if it was showing no warning signs at the start. So unless there were some signs of impending failure I wouldn't replace a rim in preparation for most tours even if it was a multi-month tour. That said I do not tour in third world countries or other places more remote than the American West, so parts typically can be had if needed.

Cracks around the spoke holes are a sign of impending failure though. BTW, they are not necessarily the result of over tensioning.