Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

On what time scales are stock support and resistance levels meaningful?
Stock support and resistance levels mean that historically, there was "heavy" buying/selling at those levels. This suggests, but does not guarantee, that "someone" will buy at "support" levels, and "someone" will sell at "resistance levels. Any "history" is meaningful, but most analysts will say that after six months to a year, the impact of events declines the further back in time you go. They can be meaningful for periods as short as days.