Should I replace my HPS? 5000 hours run time

Hello all,
I've been recommended to replace my HPS light but after doing some research I'm a bit confused. This is a 400W Super HPS (meaning it has blue spectrum as well) by Ushio.
I've looked back and calculated I have put 5000 hours run time on this. It was a Craigslist buy and the guy said when I got it that it only had 80 hours run time. He seemed trustworthy at least, so im going to trust that and hope I didn't get screwed over at that point with an already over used bulb lol. But I have gotten some good grows off this, so I think it was good.

Anyways, the manufacturer says it had 25000 hours run time on average. Other people say I should replace every 2 grows, others say 5000 hours, and others say half the given lifetime (so 12500 hours). Not sure which to trust here. Should I change it? Or keep it for a few more times around? Opinions helpful.

With 5000 hrs.,I would replace them with new ones,and keep the old ones for backups in case you have one die on you in the middle of a grow.

Do you know what precentage of lumen loss I would have compared to a brand new bulb at this point? If I'm losing only 10% lumen output these super hps bulbs are 60+ $'s. So for that cost I'd keep the one I have for a couple more grows or so. But if I've lost like 50% of my lumen output for the same power use... then yes I want to get a new one. Anybody know the specs on that?

there is a article on this on hortilux.com. so that light been on for 416 days . a hortilux is made to last 1 year with reduced lum . your well over replacement the 400 are cheap can get a good one for 30 bucks . or less.

i use these there will be other opinions on this . i used them right next to hortilux i like the ipower plants better they had more color possible the spectrum was bigger but i am using solistek ballasts . http://www.ebay.com/itm/1000-600-400-watt-Super-HPS-MH-Grow-Light-Bulb-Lamp-For-Ballast-by-iPower-/150795081291?var=&hash=item231c16564b:m:mTv1gHQL4wc7N62wY7Icpew good bulb almost free