How long are electronic ballasts supposed to last?

[Major Ramifications]

I put a few 8' light fixtures in my garage about 4-5 years ago. They are Lithonia brand from Home Depot, with four 48" T-8 tubes per fixture. One of the ballasts went bad about a month ago, and now another one is out. Is five years the typical life span of these things? The old magnetic ballasts in the kitchen have never given me any trouble in the 7+ years that we have lived there, and who knows how old they were when we moved in?
I only use the lights in the evening and on weekends.
Also, the replacement ballast I put in is a GE and it says "Instant Start", but it does not start as quickly as the others did.

Is there a better brand out there? These things are like $35-$40 at HD and I don't enjoy changing them.

Thanks in advance.

[Fast Orange]

As with most new technologies,when the electronics first came out,quite a few of the brands had problems.From personal experience,I know that Sylvania paid to have entire retrofit projects redone because of extremely short ballast life-quite a few lasted less than a year.The most recent versions of Sylvania's ballasts seem to be OK-we haven't had any returned in quite a while because of short ballast life.Another thing to remember about a lot of HD fixtures-they're built to a certain price point-they may or may not have a quality ballast.
I'm biased,but I don't think HD fixtures are a good deal-buy your ballasted fixtures from an electric supply house-you'll get better quality at a slightly higher price.
As for pricing,I believe the 4L T-8 goes for around $24.00 contractor net. from a good electric supply.

[Major Ramifications]

Wow, Fast Orange, you know some stuff about this subject. I didn't think of going to an electrical supply place for this because I figured that they don't sell retail. So, would you say that 5 years is on the low side of life expectency with the limited use mine see?

[Fast Orange]

Major-
Judging by the age of your ballasts,I think you have some of the early ballasts.I don't know if the manufacturer of your ballasts has a warranty program that would cover your ballasts,but you might try e-mailing the manufacturer to ask.With limited use-say 20 hours or less per week-yes,they should last longer than 5 years.Documenting limited use is going to be the problem for a waranty claim at this time.
Around here,most supply houses don't care if you're a contractor or not-as long as you seem to know what you're talking about,they'll sell to the public.

[UnionWelder]

99% of the ballasts in my shop are from 1980's and all still work fine 10 hours a day mon-friday....

[Fast Orange]

And 100% of the ballasts from the 80s are magnetic and use T-12 lamps-get with the program and step out of the stone age.Magnetic ballasts,with only a few exceptions,are no longer legal to manufacture in the USA.In a few more years,the T-12 lamp,again with a few exceptions,will also be a dinosaur.The EPA,as part of ongoing energy saving and ecologic legislation is outlawing systems such as the one in your shop in favor of electronic T-8 units that save 30% in energy costs and cut mercury pollution in landfills by 90%.
If you are a smart businessman,you'll check into federal and state rebate programs that,combined with energy cost reductions,will provide you with new,brighter and lower cost lighting with a payback period of only a couple of years.

[Major Ramifications]

I am not that worried about the two that I have replaced, but I just didn't want to do this every 5 years. I changed the second one last night, it was an Advance ballast and I replaced it with a GE Proline from HD for about $28.
Why does the new ballast say that it should only be used in a commercial application? The instructions specifically stated NOT to use it in a residential application. Why should it matter?

[Flatmotor]

99% of the ballasts in my shop are from 1980's and all still work fine 10 hours a day mon-friday....

UnionWelder, I'm right there with ya. I installed my T12 8' fixtures in my shop in 87 and other than lamp replacement they are still going strong. I supervise the electrical in 2 hospitals and have seen lots of T8 lamps and ballasts come and go. Other than the energy savings part of it, I am not impressed with the life of any of the brands of electronic T8 ballasts/lamps and we have used just about every major brand. I'll be keeping my T12s going in my shop until I can't buy lamps or ballasts and then I will retrofit or replace. Bill

[2LTim]

IMO, T-8's are awesome, when considering the amount of light they put out vs. the power they taketo do it. That said: If t-8's are used in a location where they are turned on and off regularly, your energy savings is about a wash when you consider the tubes you have to constanty replace.
Tim