Barbara is on a fixed budget and can't afford to pay for faster internet. She watches a lot of streaming and it buffers a lot, though. David says she can go into her Netflix settings and turn down the resolution settings to SD, which should limit the buffering. She could also watch in off hours.
The chatroom says that if her router is old, it will start buffering content a lot. A new router will definitely help speed things up. If she's just renting her equipment from the provider, asking them to give her a DOCSIS III modem will also help. Updating the router firmware never hurts either.