Most spots have a specific cause, and therefore a solution.
Pigment spots appear when melanin gathers unevenly. The triggers? The sun (80% of spots), hormones (pregnancy, birth control pill), inflammation (pimples, acne scars), aging.
What I have understood: Inflammation is the trigger we underestimate. A pimple, irritation, damaged skin, and melanin goes into overdrive.
To prevent spots, you must first soothe the skin.