Steve Screwdriver, appears once or twice
a month, about every 3 weeks on random days to upgrade the
buildings on your permanent farms.
Depending on his mood, he may just come for one
7 hour visit. Your upgrade only has to start while he is
available so have your money and your upgrade slot
available when you feel he is due for a visit.
He starts showing
up when you have at least one
building that he can help you