To ensure the springtails you purchase are healthy, consider the following tips: 1. Reputable seller: Purchase springtails from a reputable seller or breeder who specializes in live insects. Look for positive reviews and feedback from other customers. 2. Vibrant appearance: Healthy springtails should appear active and have a vibrant color. Avoid purchasing any that appear sluggish or discolored. 3. Clean packaging: The packaging should be clean and well-maintained, without any signs of pests or contamination. 4. Clear instructions: The seller should provide clear instructions on how to care for the springtails and acclimate them to your terrarium.