Mine worked perfect for over 3 years - I guess I'm the lucky one.
930254
I purchased this item in February, 2012.  It has worked perfectly, which considering other people's reviews makes me pretty lucky.  I use my printer quite often - about 25 sheets per day - but not more than 60 at a time.  I don't know how more extended use would affect the drum.

I know when purchasing compatible parts (drum or ink), it is never up to the standards of the originals. However, for the great savings, it is worth it to me to purchase compatibles; even with getting a lemon every once in a while, I am still saving money.  I am here to purchase another one.  I will let you know if it is a lemon (knock on wood).
3186145
I purchased this July 4th, 2013 and it's still working perfectly.
1123713
I was just browsing around and ran across this and realized that this is the one that I bought exactly 5 years and 2 days ago... and it's still working perfectly.

I'm bookmarking this for when I need another one (if I ever do).
1677521
I installed this a few years ago and it still looks and works perfectly.
4512838
Update- It has been 1.5 years since I installed this device and it continues to work perfectly. Therefore, I am upgrading my original rating to 4 stars. Initial rating was of 3 stars was weighted downward due to poorly written and erroneous instructions.
4254190
I had one that lasted 10 years and loved it, glad I found a replacement :) Efficient, great and reliable
4058913
I don't remember when I bought this but i'm pretty sure i've had it for more than a year. I love it so much and it still works perfectly to this day.
1068685
Works perfectly!  No problems after a year of use.
1843188
I used this for three years in my nursery to track humidity and temperature. We never had any doubts to its accuracy and thought it was a great tool. All of a sudden 3 years after purchase it stopped working. It's cheap enough & we liked it enough that we're replacing it with another of this same device.
2163070
I have read some of the bad reviews here and felt I must have been lucky.  They claims issues with parts breaking not the quality of the item working or not.  i bought one and it worked fine, so fine in fact that my mother-in-law wanted one.  I gave her mine and ordered another.  This time my wife insistedI put one in the bedroom since that is a room we spend more hours in the day than any other.  Almost, cause I still needed a third for my home office, that's where most ofmy day is spent - working. That's three and I'm pleased indeed with the quality of airr that comes out, shocking me as to what it was prior to filtering. I duly expect my step son to want one as well since he is the only apartment without one and we're all breathing clean.  But that's  just how sons and step-sons are.
2644881
worked for 3 years, it is very good for the price.
652948
My wife had one & it works great, so I got one too.
1705850
worked perfectly!  Can't ask for anything more...except I hope it lasts me a few years :-)
3810655
I've owned one of these for about 3 years and no problem until now.  The motor burned and just gave up, no problem though, can't expect it to last forever.  used it frequently during the Summer time in CA, so it was used very frequently.  Time to get a new one.  I recommend it, so I'm getting me another one like this GH900.
817756
Installed it 3.5 years ago and it still works great.
2058662
Even though I hardly use mine now but it has always served me well.  I purchased mine from a guy on craigslist back in 2004 for a fraction of the original cost and it looks and works great to this day!
2218073
I bought this thermostat from Amazon about three years ago.  It has worked great...unlike my furnace.  I came back here wondering if I could use this thermostat with my new furnace because we've had such good luck with it.  Sure enough - 3 years later, not outdated.  I'm excited to keep using it.  My only complaint would be that sometimes when navigating menus quickly or looking for a setting the device will freeze and reboot.  You lose about 15 seconds during this process but none of your settings are lost.  It may even just be a screen issue - not the whole device.  That is literally the only nitpick I can think of after three years.  Great product.