I have a 3 pc set of Uniden cordless phones (dct7085-3 2.4Ghz). I
has worked great for 2 years, then batteries were dying. So I got
some new ones on ebay, but they were cheap, so they only lasted about
2 months. Here in Canada I can buy a good quality brand for $25
each. I maybe would by two of them, but how do I know it's not a
problem with the phone, that is killing the battery quickly? Does it
make more sense to buy a new set for $100 or replace the batteries?

thanks.