2/3. I've had three so far. The first one was a startup (I was an employee) that ran out of money. The second I spent 6 months working there but I couldn't concentrate on the work and couldn't produce anything. I don't think I committed any lines of code in 6 months. I was ashamed of my performance and quit right after renewing my visa. The third job I was there for 2 months. I felt even more pressure after doing poorly at the previous job. I felt so confused even when just setting up the environment. I barely managed to do anything in 2 months and used to just hide in the toilets sobbing. I felt ashamed and couldn't handle it anymore so I quit.
4. Foreigners have lots of trouble getting apartments etc in Japan. If I just pack a suitcase and get on a plane leaving everything here in the lurch I'd feel bad because it has effects on other people.
5. Maybe 40k?