I find the remaining battery indicator is misleading. It shows 100min remaining and in 5 to 10min the battery needs to be changed. I've had these Sony batteries for couple of years. I'm wondering if it is time to replaces them?

It does sound like it.

How have they been used? How many charge cycles have they gone through? Do you run them down completely when you use them?

I've actually use them quite a bit. Did a lot of work outdoors this past summer so they definitely got put to some use. I try to run them down whenever possible and store them fully charged.