My answer depends on whether you mean while touring or in general.
For touring it was maybe 100 miles but with several broken spokes. A screw that holds the cogs together had backed out and scored the bends on all the drive side spokes. They were popping like crazy. I had to re true the wheel a few times.
In general use much longer, I am guessing it was thousands of miles. That was back when I was a kid in the late 50s and early 60s. I had a bike with permanently broken spokes that I never bothered to replace. I just twisted what was left of the broken ones around an adjacent spoke and trued it up the best I could.