These outdoor flood lights blink, flash on/off or go out entirely when they are defective. Sometimes it appears to be a defective lamp, while other times the ballast will need replacement. These new ballasts have the capacitor glued directly to the transformer. The manufacturer clearly wants you to spend your money on more replacement parts than may be necessary.

Is there an easy way to tell just by observation alone which component is bad? In other words, does a bad ballast Vs a bad capacitor or lamp have different behavioral characteristics?

There is also a starter component needed for HPS ballasts, which is included with the cap. Yes sometimes the individual components fail, and if they are separate, you can replace them, but if made or assembled as a unit, then the entire unit must be replaced, to avoid violating UL listings.

The HPS lamp blinking on/off is a typical characteristic of this type of lamp at the end of it's life.

The longer a lamp near the end of life is allowed to remain operating, this causes additional stress on the ballast,cap, and starter, and can cause premature failure of the ballast kit.

Best method to lighting maintenance is to replace lamps before the rated life of a lamp is reached. This is calculated by noting the published mean(average) rated life of a lamp, compared to the actual hours of operation, and re-lamping before lamps begin to fail.

This will help save ballasts, and produce a scheduled program of insuring having a maintained lighting system, so you have the light when needed.