I sucessfully finished my first grow, and I was wondering if I should replace the bulbs for a new grow, or just how often I should change the bulb, if not wait until it gives out (potential fire hazard? it is in a glass covered reflector). thx guys
H.I.D. bulbs have half-lives, meaning they slowly emit less light the more they are used. Because of this, you not only have to consider how long the bulb might last, but also how dim you'll allow it to get before replacing. Running HPS's 12/12 for 9mo/yr, I replace the bulbs every year to keep them at their brightest. With this schedule, someone primarily trying to get their money's worth from the bulb might keep it as long as 2yrs. So about every 1-2yrs depending on your priorities. And btw used bulbs can be sold for maybe a third of their original price, so when you replace them, you only end up paying 2/3 the cost.