How do you tell when an HPS lamp needs replacing?

Besides doing it by changing it out in set periods of time and knowing how long it's been previously ran?

I am wondering if my bulb needs replacing..
I bought it from someone who used it for a few weeks and got a different blue spectrum bulb he said he liked better..
The filament wasn't blackened at the time like it is now on the edges..well greyed at least..it looked new when I bought it..

Now it has some edges burning like this:


It looks just like that..
I have used it aprox 2 months for 12on/12off..
I know the guy I doubt he lied to me and I saw the stage his plants were in but he could have used it a crop before or bought it used too who knows..but it did look brand new at the time.

Anyone have any thoughts or suggestions on if this should be changed out?
I'm new to all this could use some help.

Thanks

if in doubt,change it but hang onto it for a spare

mrmadcow said:

if in doubt,change it but hang onto it for a spare

Click to expand...

Thats sound advice, I would also replace it if no one can honestly tell ya how long its been in use. A new bulb is like using windex on your windshield. Just do it