I empty so I can receive

I am a conduit

I don't have to hold onto what I have today in order to perform well tomorrow.

Fresh water is always on the way, always available.
It will come tomorrow.
If I give what I have today, I can receive fresh water tomorrow.

I empty so I can receive.

I don't have to give more than I have today.
I literally can't.

And I don't have to reserve what I have today for tomorrow.

I am a conduit.
I can let it flow.