Computer Life Span

It's been six years since I had this one and only changed a GPU once

I have found that laptops last about a year.
Decent Towers last until obsolescence, which has really slowed down the last few years.

Computer's life span depends pretty much on... user. Why? There are several factors, for example used OS, apps (AV, background apps, services/daemons, monitoring tools, other security tools), their configuration (it tells applications how to work), maintenance (sometimes system needs some tweaks form time to time) how many processes are running in background, way user uses computer... those are different for people. Depending on them old/low-end computer can easily/smoothly do work new/high-end may have problems/lag with. Basically the older is computer, the more maintenante/work it needs to work smoothly... of cource one doesn't need much maintenance if it is set-up properly from beginning. 5-10 years shouldn't be any big deal here.
Very important factor can be supported instructions/extensions/technologies, eg. sometimes games may now work without proper shaders, DirectX, OpenGL; some other applications without proper SSE et cetera et cetera.
Basically most often repaired/replaced components in my experience are: PSU (ATX is working no matter computer is powered on or not; most common are problems with electrolytes), GPU (overheats/artefacts on screen or performance issues on low-ends) and SDD (well, many of those have quite limited life cycles so if there's no HDD they may "die" fast if you write/download/install much). Some components may require some extending like RAM (after couple of years), HDD or other drives/readers to support new storage types. CPUs - I don't remember seeng any problems with performance with them, even old ones. GPU/CPU usually require replacement for thermal paste or equivalent after... about 5-6 years.

I know people having problems with computer after 2-3 years and some other using over 10 years old hardware to do same work :D

Haven't gone upgrade crazy in a couple years, and I haven't had to change much at all. For most people the main reason to upgrade is games. Gradually you need to turn settings down lower and lower, until finally you get sick of it and buy some shiny new thing. :)

Have had a motherboard and some video cards die, but fortunately there's been a spare around while I RMA the broken one. Most annoying thing was to have a boot drive die, fortunately had a backup but it was just out of warranty so I got to eat it. :(

Hmm, that reminds me, you may not think a ssd is worth the extra expense, but there's dozens of little things that are slow with a mechanical drive, but happen instantly with a ssd. So if anyone is still looking at parts I'd say get more ram than you think you need, and get a ssd. Have fun. :)

Depends on how good your parts are :P for example, seasonic psus are going to last longer than diablotek's because they are more efficient.

Laptop, since 2009, still exactly the same as I got it.

18.4", 1680x945 hipster resolution
500gb HDD
4gb ram
Core 2 Duo T6600 2.2ghz
Nvidia 240M 1gb

It serves me well, but there's certain games I am physically incapable of running no matter how low I push the settings.

Acer laptop, lasted for 4 years. Still working though, but you can fry an egg on it so I had to stop using it.

Have mine since 2006, changed the videocard and added 1 more HDD. Also recently my MB died, so changed it too.

My current one I've only had since October. The one before that was a Lenovo laptop that I had for just a bit over three years and the one before that a Toshiba laptop I had for 6 years. The Lenovo was still working, I just wanted a graphics ad cpu upgrade.

I got my pc since 2007, i still have a dual core 2.00Ghz intel e4400 ranked #1100+ in top CPUs of all time, only changed motherboard and videocard in 2009 after GTA 4 launched on pc, i still got 2GB of RAM @ 333MHz and that's about it. I play most games on lowest settings, i get like 30fps on dota2 with medium textures and everything on low, a bit higher fps on CS GO using fps config, and same for TF2... but guess what? New pc in 1 week :D

Built it 8 months ago. I'll build a new one in a few years

Gaming towers of power usually last for about 10 days, hurry up and get it on ebay before it turns into a pumpkin.

I still have a system from 1996. Last time I checked, maybe three or four years ago, it still ran fine. As long as I ignore the Y2K and daylight savings issues.

I used to have an old Toshiba laptop that weighed over 30 pounds, white shell that yellowed over time. The last time I saw it, it still worked. I used to emulate Dragon Warrior III on it. I last saw it around 2001.

For a gaming PC, I tend to replace the GPU every five years or more, it depends on if the games I'm playing require a better GPU. Same with the CPU. Since it takes so long, I wait for sales and new tech announcements. You can easily save 50% or more on last year's best gear if you wait for the new stuff to come out, and then watch during holiday sales. No games ever require the very latest hardware.

About 5 or 6 years...can't remember exactly. Considering I have crappy hardware (like 2 GB RAM) and been running almost every game for as long as I had the PC, it has been able to keep up. Only cleaned it once a few months ago. Although, it is starting to show it's age. don't have much HDD space, the RAM is starting to become an annoyance etc. I'm planning to change it soon.

Oh and never changed anything on it.

got my gtx580/i7 950 combo for almost 2 years now(most parts of my build were in use before i got them, for about a year).
i had to replace the PSU 2 times by now. my PC is still alive and kickin' so far.

how long a computer's lifespan is, depends on the quality of the hardware and how you're using them.
for example, if you're using your PC for very CPU demanding tasks very often, such as video-editing/converting/compressing and on top of that overclocked the CPU, the CPU's lifespan will decrease. you can just reduce that effect with a good cooling device.

Got my original desktop in 08.
Replaced the ram that I thought was faulty after 2. ram was fine
Upgraded the gcard 9600GT 3 years after purchase (1 year after ram). 460GTX
Did a complete upgrade about a 9ish months ago and replaced everything. Sold my old parts and they are still working fine.
My mother's computer, she's had that thing for 12-15? years. Only thing changed on that thing was mouse and keyboard.

Computer can last a long time if you take care of them, or they can break for no reason.
If you want to keep a good gaming rig going, a gpu upgrade every 2-3 years if going from mid to mid level, or 1 year if going for flagship to flagship card. CPUs can be fine for 4-6 years depending on what one you buy. People are still rocking the original i7's with no problems. Ram, ram never changes.
As for actual life, without worrying about keeping up with gaming or anything like that, well you can expect 10-15 years if youve bought the right quality parts and dont have an accident like a lightning strike or something.

My desktop is 4.5 years old. I replaced the graphics card, CPU, case, motherboard, RAM, added an SSD as a main disk and another HDD, external HDD, blu-ray burner.

In 5 years I switched a dead motherboard, bought a new graphics card, bought a new cpu fan, upgraded ram, switched my power supply, then again put my old one back in because the new one broke. That's it, my 5 year old i7 920 is still kicking for now.