Ah interesting. The lamp is nearing the end lol. So far, the three GE SPX35 EcoLuxes from 2006 (original to the fixture) are still going in my F32T8 Lithonia IS troffer. I have one spare 2006 SPX35 GE left to use as a replacement for one lamp when it fails but after that I'll need to buy new lamps. I'll probably still just buy 3500K GE lamps (which would probably still be SPX unless Lowes only sells SP, though I think they stopped making the SP and 700 Series lamps? I still see them online though). I'll only replace the failed lamps though. If it was a commercial installation I may replace all the lamps to reduce maintenance calls but in my own fixtures I have plenty of time on my hands to replace bulbs right now (in fact, I almost look forward to bulbs in my house going since I then get to service the fixture lol, then again, these SPX GEs are the original lamps to the fixture, so I don't want them to die since they're original and I think that's pretty cool. The lamps are jet black on both ends though (except for the center lamps, which is only totally blackened on one end and has only black spots where the electrode stems are on the etch end). I'm not sure why the center lamp has a different wear pattern but they must be the original lamps since they were still installed in the fixture when they removed them. There were three of them removed in total. Only one had a parabolic door/louvers so I took that one and I took all the "guts" out of the other two (ballast out of each, sockets, and lamps). The two other fixture top housings ended up in the dumpster. There was a lensed troffer down there too that was really ratty but I never got to it (I would have taken the lamps, sockets, and ballast out of that one too).
Lamp life has a lot to do with the frequency that it's switched. If the lamp is in a residential place but in a frequently-switched application, then the lamps will not last on any ballast other than RS. The light in laundry room is frequently switched and I'm surprised the lamps aren't near already to be honest. They were jet black on the ends when I got them so I figured they were right at or near EOL. They probably wouldn't light on magnetic T8RS or they'd at least struggle.
The most recent lamp I've changed that has actually burned out was a 40W GE soft white incandescent I installed in my brother's room after one of his CFLs died. Back quite a few years ago (well, around 10 I guess) we had gotten some 13W GE CFLs and we had installed them in the kitchen/dining room (four in each of the two fixtures) and they were installed in my and my brother's rooms (three in each bedroom). Everything else remained incandescent. Then I bought LEDs for my room in April 2012 because I couldn't stand the CFLs in my room and didn't want the heat from incandescents (I like to keep my room as cool as possible, when it get's cold I just open my heat vent to warm it up). One of my three CFLs ended up in one of the "boob lights" downstairs. Another ended up in the "mushroom light" over the sink, which has two lamps. The third eventually ended up in my parents' bedroom fixture, which also has two lamps (their room is bigger than mine and my brothers yet we both have three lamps in our rooms and they have only two lol).
Then, one of the CFLs in my brother's room died, so it got replaced with a 40W Philips incandescent. The CFL miraculously came back to life after tinkering with it, so it went in one of the lights next to the front door. (It stayed there until we replaced the lights next to the garage, when I replaced all four lamps out front with halogens.) So then that CFL ended up somewhere. Maybe I just stuck it in the recylcing box at lowes to get rid of it... Then the Philips incandescent died and I stuck in a use 40W GE SW from my dad's parents' dining room fixture (from when I stuck in halogens for them so they'd get more light without raising their bill by a lot) Then last week the GE died so I stuck in an NOS no-name 60W incandescent. So now his bedroom fixture has a 60W SW incandescent, an IS GE CFL, and a PS GE CFL. My room still has its three LEDs. I forget what lamps are in my parents' fixture since the cover fully encloses the lamps, but one is a PS GE CFL since there's a second-delay before the lamp comes on.
Out in the kitchen/dining room (my kitchen, dining room, and living room is all one big open studio-style room with a high ceiling) the dining room ceiling fan had all four CFLs still working. The kitchen chandelier had one CFL fail, which I spot-replaced with an enclosed A19-shape MaxLite CFL. Then a second one was spot-replaced with another MaxLite CFL. Finally, I decided to just replace all the remaining exposed tube CFLs with MaxLite enclosed CFLs since the enclosed ones look better. The only downside is that the stupid things take like three minutes to reach full brightness, which I usually don't mind, but it's nice to have instant-full-brightness light sometimes, especially when I'm home alone lol. When I'm home after dark I leave a lot of lights on lol. I don't know why I'm so paranoid of someone breaking in, but I just get nervous when I'm home alone. Not sure why. I forget what the mushroom light over the sink has but the hallway mushroom light still has both original 57W Sylvania SuperSaver lamps. I've replaced the kitchen sink mushroom light's lamps quite a few times but I haven't recently, which leads me to believe there are CFLs inside there.
As for the ''boob'' lights in the basement, thre are four, two "main" ones that share a switch and get the most use, and the other two are on their own switches, one gets moderate use and the other rarely sees any use at all. The latter was the fixture I took the original 1999 Philips 60W SW incandescent from, replacing it with a 57W "energy efficient" SATCO inside-frost lamp. The ones that share a switch have had their 60W lamps replaced a few times over the years. The one near the computer (on its own switch which sees moderate use) originally had an incandescent, then it had one of the CFLs from my room, then it had a 60W GE reveal which lasted a month, then we finally bought four 53W GE soft white halogens and I group-relamped the three that see regular use. Then recently I had to replace the twin-switched boob lights since the lamps were super dimmed and one finally blew out. I left the GE halogen in the single fixture since it's not really dimmed out much, though it does seem dimmer than the new Sylvania clear halogens. We'll see how much longer the Sylvanias last... As for the 90W SuperSaver keyless sockets, they actually never made it long enough in service to burn out. The one in the laundy room had a big CFL with a worklight reflector for the longest time since the 90W incandescent wasn't enough (dunno what happened to the 90W lamp). Then I replaced the utility room keyless socket and the laundry room keyless socket with F17T8 fluorescents (which were superseded by 4ft fluorescents) and then one of the two garage keyless sockets was replaced with a duplex outlet for the fluorescent lights out there. There's only the one remaing 90W keyless socket left, and I think it's there to stay. I don't think my dad is up for drilling anymore holes in the drywalled ceiling since we missed the joists a few times lol. One of the removed 90W incandescents is now in use at my great-aunt's house in the pull-chain I used to replace the pull-chain WE F20 fixture in her basement. The other 90W SuperSaver was in use in the 60W-MAX mushroom light over the sink, but it died and was replaced, I think by a 13W CFL. I don't know if the CFL is still around, but both lamps, whatever they are, are still working.