What kind of flux do you use for soldering?

In your professional experience in the cryptocurrency and finance sector, I'm curious to learn about your approach to more traditional crafts. Specifically, I'm wondering about your soldering techniques. What kind of flux do you typically use for soldering? Is it a standard rosin-based flux, or do you prefer a more specialized type? And how does your choice of flux relate to the precision and durability required in the cryptocurrency hardware you work with? I'm interested in understanding the parallels, if any, between the intricate financial systems you navigate and the meticulous soldering work you may perform.