What Am I Riddles

Question: Those who make this item, don't use it. Those who BUY this item, have no need for it. But those who USE this item, never see it. What is the item?

Question: I run out of battery but never need to be changed what am I?

Question: A box without hinges, key or lid, yet inside, gold treasure is hid. What am I?

Question: I can be found all around the world I can be stricken but not feel it Both the moon and the sun know who I am I can be seen twice a day and 730 times a year What am I?

Question: I dig out tiny caves, and store gold and silver in them. I also build bridges of silver and make crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs my help, yet many people are afraid to let me help them. Who am I?