MAC energy consumption question

[NeptuneMidheaven at aol.com]

Hello Everyone,
I have a question I'm hoping you good folks can answer.
Trying to accomplish two things.  I'm trying to make my 4 year old Bondi blue 
IMAC last and I'm also trying to cut down on energy consumption here.
Is it better to shut down every night or just stay in sleep mode and (almost) 
never shut down??
Last year I replaced the AV board and am thinking it might be better to turn 
it off and on (once daily or less) in order to extend the life of this 
(refurbed) part - as well as save $ on the energy bill.  Does it really make 
much of a difference??
Thanks,
Val