Answer:
I occur twice in eternity. And I'm always within sight.
You fill it and it empties, A metaphor for plenty, Depending on what half you see, It's either full or empty
Many foods can make me strong but give me water and I won't last long.
Doing something of this nature is likely to land you in court
The profession of Jimi Hendrix and Eric Clapton
My days are numbered.