Replace Globes How Often

hi just wondering how often you guys recommend to replace globes ive been told every 2 or 3 runs any opinions?

if you have a light meter you can check and see when you have lost a certain percentage of efficiency and replace
I personally replace after 3 grows of 12/12

but it may only be part of the light spectrum that it looses i think its the phosphorus or something that goes first so light meter may not do the trick.

I try to keep it simple and in doing so I have results I am more than happy with and that exceed most others. I don't waste time trying to be a scientist or engineer I just share what works best for me. BUT I do know that if you use 1000 watt bulbs that are old and give off lumens equivalent to a 600 then you're wasting money and potential bud

yeah i agree mate i get very good yields too just trying to keep improving them hehe