Answer:
I'm blue, but when you see me I'm red. You don't see me too often. I'm there for you if you're hurt, but I'm good for you. What am I?
I'm not alive but I grow I don't have lungs but I need air I don't have a mouth but water can kill me. What am I?
What is easy to get into, but hard to get out of?
I go around a yard but do not move. What am I?
A sport with love and service played by singles and pairs.
No matter how little or how much you use me, you change me every month.