Being good at everything (allrounder)

I think it is normal for everyone to expect a person good in one field to be generally good in others and that might be true. But I have come across people who are narrowly focused in their domain, that they might not be good at anything else. Technology is growing at such a rapid phase that it is not possible to keep up and be good at everything. So here's a suggestion

1. Be good at what you do
2. Use common sense everywhere else (including above)