Hmm...
eTrex (bought 2004ish): Sold after a couple of years, in full working order.
eTrex Legend (bought 2007ish): Still have it, still works fine.
eTrex Vista HCx (bought 2009): Still have it, works fine but the rubber band started to go after about 3 years, re-taped to keep it going for another year, but now too slack to line up with the buttons properly.
eTrex 30 (bought 2013): Still working, but the 'back' button is on borrowed time.
eTrex 32x (bought 2021): Shiny and new, but disappointing murky screen (see above).
There seems to be an inverse relationship between the quality of the software/features and the quality of the hardware. The Vista HCx was by far the best software-wise for cycling, on account of its clear turn instructions and ability to make a contemporaneous copy of the recorded track on the SD card that was very hard to accidentally delete.
The eTrex 30 appears to have been the sweet spot, and was certainly the best iteration of the hardware. I reckon 7 years is a good innings for a tactile switch behind a rubber membrane. But it's clear that Garmin can't be arsed with developing the eTrex series any more - the real money is in short-lived fitness devices, and they concentrate their innovation on the bulkier higher-end outdoor units.