How to determine remaining bulb life?

Hello, I have am going through the HPS bulbs I have stored away and the majority of them have around this much use:

Some have burn marks on the bulbs, is it dangerous to use them? Does this effect lumens?



How much of the tube blackens before major effects to lumens?

I tried searching for forums on this but it pulls up a lot of different topics. Threw some tags on this thread.

I found bulbs that had little to no use and am going to use them to bud my current crop; but I would like to learn about judging bulb life.

Thanks for any input. Heading to my cold pillow and warm woman. Night all.

They slowly lose their brightness.

You could measure the lumens on a new bulb and keep measuring every 3 month or so to see the difference.

The burn marks are not dangerous.

I don't know how much they lose but I use them til they pop

There fucked I had the same problem cant remember what problem was.
I think it was just cheap bulb or bulbs didn't suit the ballast
If u get a good bulb set up beside the burnet out one u will see the different in them

Cheap bulbs cannot work longer, good ones after 2 years working the glass still clean

I use em for 3 grows n super charge the last grow. Choice of bulb is sunmaster,cheap but sassy

Get a light meter and check what they're putting out

When I grew under 400 watt MH, I was a cheapskate…plus the bulbs were expensive…and I never knew to check/change them. I thought they would just work at the same intensity until they burned out…but NOOOooo! I found out when decided to get a HPS conversion bulb (worked on the MH ballast). I put the meter under the light and it was a strong reading. A few months lateral I checked it again and the light had gotten appreciably dimmer. But my eyes didn't notice the change because it happens over time. The light meter didn't lie! And the real bitch was that the fixture was still drawing all the power, but providing only a fraction of the light.

Light meter, bro.