Light Cycle?

So, I've been wondering since autos aren't as photogenic.

Can I say.. Leave the light all day.. And give it 4-5 hours of darkness.. And then leave it all for another day or two for 24/7... And then give it a little more darkness?

Basically, I wanna just give it darkness whenever I want(when I can get around to it)even if it's a couple days out of the week... If so, does this mean I don't have to do it at the exact same time the last time I did?

Sorry if there's confusion

yes its fine
im random wtih mine if i have company over that isnt hip to whats up
or it warms the house up too much up with my oldlady cooking or baking something ill shut them down
i have just a box 3x4x5 and if i shut my fan down it will get over 100f in around 5 mins its like a heater lol
270w of led 400w hps and around 400 w of cfl