should i change my bulbs I need your opinions

when should u change ur bulbs. i have 2 400 watt lights and i run 2 m/h conversions and 2 hps bulbs ive read that u should not wait till they burn out becuse they lose lumens after a while but how long should u use them before they become a waste of energy ive been growing with these for about 2 years so the question! Is it time to change them even though they still work.

I change out every other christmas, cause i ask for them from my wife i dont remember how long they last. U can google it and come up with it. Good luck, smoke well..

You'll get a lot of different answers, but if you've had a few for 2yrs, then yeah, it's definitely time to change those. I remember the huge difference I noticed in intensity when I changed an old MH bulb that I was vegging with. I've also heard of people saying that you should change your bulbs after every 3 or 4 grows, which is more or less how I do it now.

ya all 4 of mine have about 7-8 grows on them now so i think im gonna change them