I tend to think that an in-wall light switch should last twenty to thirty years. However, I’ve had to reset my expectations with smart switches.
I’ve had a several decora GE Jasco Z-Wave switches in my home for the past 10 years. Four of them lasted seven years before the electronics completely failed. I replaced three of them with new Jasco switches, and one of them with a dumb switch. When another switch stopped reliably responding to button presses after nine years, I replaced it with a traditional “dumb” switch. Another two Z-Wave switches are still going. Of the two, one is used multiple times per day, and the other one is used a few times per week.
Compared to dumb switches, smart switches contain additional complicated electronics — integrated circuits, capacitors, resistors and diodes. They’re more subject to age, “dirty power” and other environmental factors. High quality components can extend the expected lifespan.
There have been a few times when the switches stopped responding, and I’ve had to reset them. They have a small tab to pull, and then push back in. It’s like resetting a GFCI, only more difficult.
Z-Wave has had staying power, and Z-Wave devices communicate locally, so are not subject to the whims of a cloud provider who might decide to end support, or to economic forces that might shutter a business, leaving devices without cloud support. Still, the staying power of the cloud provider, or of a technology, also has an impact on the liftetime of a smart switch.
I expect smart switches to last 7-12 years, and to be less reliable than traditional switches. Is the convenience and automation worth it? Sometimes, yes. Other times, no.