Thanks for clarifying! I do think in a context like this one, where people are thinking about why offices etc don’t install far-UVC, your friend’s phrasing is likely to confuse people. For example, if I recommended someone not buy a car because it only had a one-year lifespan, I think they’d be grumpy if they later learned I meant it would only last one year of 24⁄7 operation. When we talk about “lifespan” we’re normally bringing in assumptions about expected usage.
Thanks for clarifying! I do think in a context like this one, where people are thinking about why offices etc don’t install far-UVC, your friend’s phrasing is likely to confuse people. For example, if I recommended someone not buy a car because it only had a one-year lifespan, I think they’d be grumpy if they later learned I meant it would only last one year of 24⁄7 operation. When we talk about “lifespan” we’re normally bringing in assumptions about expected usage.