I think the ideal solution is somewhere in-between the above two extremes. Charging fully at a supercharger is tedious, because the last 20% takes about as much time as the first 80%, so you are basically doubling the wait time from ~30mins to an hour+. On the other hand, cutting too close and being forced to drive slowly to reach the next charger is both frustrating and risky (e.g. in case there is any trouble on the road forcing you to a detour).
It is best to come up with a realistic estimate (taking into account temperature, elevation change, wind) of how much energy you need, then add a 10%-15% buffer and charge to that value.
For the estimate, you can use a tool like this:
EV Trip Planner