Amadeus W. M. wrote:

1) How much power (watts) does a cord mower consume? I imagine more than
a light bulb, but I don't want to pay hundreds on my already high electric
bill.

It's cents rather rhan dollars. Let's look at the Black & Decker web
site, for instance:

http://www.blackanddecker.com/Outdoo....aspx?RHID=596

Their mowers are rated at 12A, which at a voltage of 120V will give you
something in the order of 1kW, so you can run it for an hour for 1kWh.
The cost of electricity in the US is in the order of 10 cents per kWh,
so you can run your mower for an hour for 10 cents.

2) If I buy a cordless mower, what's the lifetime of the battery? Does it
last less over the years? I want to be able to finish the entire lawn
with a single recharge, even after, say, 5 years from now.

No idea about cordless, but if your land is 0.22 acres (or 9,600 sq ft),
I would go with corded (I have 6,000). You can reach the whole of your
property with an extension cord and you don't have to worry about
charging the battery before use or the battery lifetime or anything
else, the power grid is always there

Paulo