If you trade fundamentally, averaging down makes sense. You are betting on something solid: company earnings, future products.......That's perhaps what investment is understood traditionally, the Warren Buffett way.
If you trade technically, you need to compare the gain and loss of averaging down and cutting loss.
Scenario 1: You buy a stock at $20, and it drops to $18. You double up. When it goes back to $19, you sell and breakeven.
Scenario 2: You buy a stock at $20, and it drops to $19.50. You sell and take a loss of 50 cents. When it drops to $18, you buy. When it goes back to $19, you sell and make $1. Subtracting the loss, you have a profit of 50 cents.
Scenario 3: You buy a stock at $20, and it drops to $19, you sell and take a loss of $1. When it drops to $18, you buy and then sell at $19. You breakeven.