Our number is two no more no less,

You cannot avoid us we must confess,

We are the only two certainties that will happen to you,

Before you realize it you'll be victimized too,

But there is one factor that you must know,

Only one of us can give you a life-ending blow,

But don't think you are safe and there's time to relax,

The other will reduce your paycheck just like that.

What are we?