When soldering MCU (Arduino and like) to perforated board I apply solder only to the pins in use, leaving the unused ones just sitting in the hole. I do this to minimize soldering accidents. The headers themselves had all their pins soldered to the chip.
It's this a good practice?
Best Answer
No, it's not good practice. Obviously, the header will be better fixated mechanically if you solder all pins.
For this kind of task, I'd expect very little soldering mistakes to happen, so go ahead and do it.
Furthermore, this is confusion waiting to happen if you decide later on that you want to use a pin you haven't soldered yet.