I shave every day, but my beard stays the same. What am I?

Who has married many women but was never married?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?

It's pretty hard to give up.
If you remove a part of it, you will be left with a bit.
Even if you remove another part, the bit still remains.
Remove one more and it still remains.

What is it?

I’m tall when I’m young, and I’m short when I’m old. What am I?

I am green and found in the forest and have needles instead of leaves. What am I?
Hint 1: It can be used for Christmas decorations.
Hint 2: I have a strong, scent that is used in air fresheners.