My "big laptop" (HP DV6T) is 6.5 years old. It still runs okay but battery is dead, so I have to leave it plugged in if I want to use it. It served me very well, but now I just keep it under the bed at my mom's house in NC for when we pass through there and use it for backups.
Last October I bought a little Asus Transformerbook T100. It's a hybrid tablet/notebook and the perfect size for trave6l. It has very little disk space, though, so I had to put most of my older photos on a memory card, and I have to be careful with space, deleting stuff frequently, not downloading a bunch of junk. I love this little computer, though, since I don't have a Smartphone. It serves as an e-reader as well as my main computer now.
In the past my various desktops and laptops lasted around 6 years or so before they got so slow and unwieldy I decided to buy new. And always at that time, the technology had gotten so much better, my new system was both cheaper and WAY more powerful/faster/more storage than the previous, so I never minded changing.
Cameras, I had my last digital for a loooooong time, maybe 7-8 years, but I finally ended its life by dropping it hard on concrete. So I bought a new one last year, and it is already showing signs of wear. Doubt I'll get 7 years out of it. Once again, they have gotten cheap. I was happy to get a new one as I love the 12x optical zoom. That used to sound impossibly expensive, but now it's certainly not anywhere near top of the line.
Planned obsolescence is alive and well in tech gear. I never feel that I have to have the latest and greatest, though. I'm too frugal!
Emily
2011 Jamis Dakar XC "Toto" - Selle Italia Ldy Gel Flow
2007 Trek Pilot 5.0 WSD "Gloria" - Selle Italia Diva Gel Flow
2004 Bike Friday Petite Pocket Crusoe - Selle Italia Diva Gel Flow