I am in the US and just doing my own repairs and building.

Do I need to use any of the lead free solder to repair the boards that
were made usign the lead free solder?

I have not bought any yet and have been practicing witht he SMD on old
computer boards. That stuff seems a pain to work with compaired to the
'regular' tin/lead that I have been using for the last 50 years.

I have been thinking about getting some for the power transistors and
resistors where there is a lot of heat build up but not sure if that
application would even be worth the trouble.