I think I would always only make a decision when I was faced with the particular situation, right there.
To be honest, I trust my judgement. If it's not obvious to me whether to lie or not lie in a particular situation, I'd just go for one (perhaps on a whim - like going ip-dip-doo at a polling station, perhaps it'd depend on past experiences, perhaps I'd tend to avoid lying because of Christian teachings - opting to withhold details instead). Then if it turns out that was the wrong decision later on, I'd just think, 'oh well, I'm a human, I'm gonna make mistakes sometimes. The answer wasn't clear to me.'
I wonder if I'll be a ruthless doctor in the future...
I'm caring, honest.