While the limited lifespan of electrolytics is well known, I'm very curious as to the lifespan of the humble yet ubiquitous 0.1uF ceramic disc capacitor. There must be billions of these little buggers in digital electronics, and I've never seen one go bad from age.
Interestingly, they also claim the ageing of ceramic caps can be reset by baking them at 150C for a couple of hours. Many electronics board could survive this, which seems to imply that a digital board which used exclusively ceramic caps could in theory last ~forever (> 1 human lifetime).
I can tell you that most vintage radio and audio guys generally don't bother replacing ceramic capacitors even on 70-80+ year old equipment, so my guess would be 'a long time'.
Most of the time the failure mode is excessive leakage. Which often doesn't cause problems. And ceramic and tantalum capacitors tend to heal if running at more than a few volts. I found a cap on battery backed up memory array that was sucking about 50uA. Putting 5V across it 'fixed it'
Just a couple months ago I found a 27" LG LCD TV from 2005 near a dumpster. Cuirously enought the faling part was some 6K 5nF ceramic capacitors in the internal power supply board. All were kind of burnt, some a little, some desintegrated.
Truth be told there were videos in youtube on how to fix the exact same model.
You probably see more decline in capacitance just by running an MLCC close to its voltage rating than you do for a decade.
Many of the datasheets will show you the derating curve over voltage. Run a 6.3V X5R cap much over 3.3V, and you'll see the effective capacitance decline precipitously - 50% or more.
This site claims "For X7R and X5R the loss is calculated at -2.5% per decade hour and for Y5V it is -7% per decade hour." https://www.johansondielectrics.com/ceramic-capacitor-aging-... but that seems very pessimistic.
Interestingly, they also claim the ageing of ceramic caps can be reset by baking them at 150C for a couple of hours. Many electronics board could survive this, which seems to imply that a digital board which used exclusively ceramic caps could in theory last ~forever (> 1 human lifetime).