I have been using the same HPS bulbs a full year now for at least 12 hours a day and sometimes all day. I know they deteriorate over time but by how much? Are we talking like 10% light loss or more like 50%? How often should I worry about switching them? Also, is there a significant difference between the expensive brand-name growing HPS bulbs and the regular basic HPS bulbs that cost 1/3 the price? Thanks in advance duders.
I buy a new bulb every year! Just to make sure it is good to go! I really do not know how long they are really good for, but it is better to have a good light and produce some nice buds, then small buds.. As for the cost, you need to look at the light spectrum and see what the difference is between the 2. If you have a local hydroponics store, they will be able to give you a better answer, as they should know thier products and the difference!
if u go to your hydro store they will say on adverage the bulb will last at peak power for 3 months but the globe itself will last longer they say this to make money dont be fooled!!!! A light can last for 2 yrs even but id change it every 6 months to a year to keep it safe as the other posts say
If you still have the lamp's manufacturer's packaging it should tell you on it. My 430w HPS for example has an average lamp life of 16,000 hours.