People's concepts of light cycles are strange. Everyone accepts (correct me if I'm wrong) that switching to 12/12 to flower is essentially to 'trick' the plant into thinking summer is coming to end - hence it starts flowering. Yet in the veg phase you're not 'tricking' the lady to do anything, you just want her to photosynthesise (ie. combine light energy and nutrients into visible growth). 24/0, 18/6, it doesn't really matter, you have to suit it to whatever your personal needs. I veg on 24/0 as I don't have a spare timer and can't be bothered to go buy one, but I'm lazy. If we're talking equipment longevity, then maybe (don't quote me on this) every time you ignite a lamp (hps/mh/cfl) it shortens its potential life? So leaving it on all time perhaps means it will last longer and brighter etc.?? Any experts...? What is the degrading effect of lamp ignition?