I agree that a second battery is a good idea. Although a charger could fail, they are pretty unlikely to go, and even if one did, you can likely buy another one in most American cities. A battery is a much more likely failure - although more than likely, the failure is a human one than an outright technical fault. (e.g., forget to charge it, run it too long, too many LiveView, etc.)
Ballpark camera life expectancy for most folks will be "longer than necessary." 50,000 cycles doesn't sound like very much compared to the current pro cameras that have a design life of 400,000, but if you average 75 frames per week every week, the 50k will last you nearly 15 years. It's certainly possible to use the camera more - but most people don't, not by a wide margin.
As far as battery life goes, my D100 batteries (similar but not identical design to your D60) are still entirely usable - and I got them in late 2003 or early 2004. They haven't had as much use as my later cameras, but probably not an awful lot less than what most D60's see. I have about 26,000 frames on the D100, about 3300 per year, or about 65 per week. (My main cameras do about 25,000 per year between them.)
_____ Brian... a bicoastal Nikonian and Team Member
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