unstable power supply

Heya all, just want to ask this to clarify is it necessary to switch off my Power Supply after I'm done using my PC? Well because I live in South East Asian country (Indonesia), my electricity here is very unstable (rated 220-230V, but it often drops to 160-ish), hence why does it necessary to...

I put my PC in for diagnosis nearly 3 weeks ago. The problem was, I spilt some water/gel from a dehumidifier onto the motherboard. (It never completely drenched it, just some splashes) between my GPU and the CPU. The PC was plugged in but not powered on. I immediately unplugged it and used some...