Having lights on 24/7? effects

well i was just wondering how long is to long to keep a plant on 24/7....i kno you can keep seedlings on 24/7 but what about veg ? can u veg a plant on 24/7?

then just throw it into 12/12? or do u need some 18/6 in there?

and will 24/7 eventually kill a plant? do they need sleep?
thx everyone

you can do 24/0 to 12/12 but i think it's better to veg with 18/6 then move to 12/12. it's less strain on the plant, and it gives your plant a chance to rest and get use to a sark cycle. Again you CAN veg 24/0 or 18/6... some people will argue that 18/6 is better some will say 24/0.. 24/0 will give you faster growth but i like to start 24/0 for 2 weeks then 18/6 the rest of veg. IMO