Using your D'Addario J74 phosphor bronze mandolin strings is easy. First, loosen the old strings and remove them from the mandolin. Then, thread the new strings through the bridge and peghead holes. Tune the strings up gradually to the right pitch. When you're done playing, wipe the strings with a clean, dry cloth to keep them clean. Don't expose the strings to extreme humidity or heat, as this can cause corrosion. If you notice the strings losing their tone or becoming dull, it's time to replace them. With proper care, these strings will give you great performance for a long time.