I recently re-wired the phone installation in my apartment and found that my line's drastically improved in terms of quality. DSL was always ok, seems to comfortably carry my 3mbit/s ISP connection.
However, it was interesting to use a dial up modem as a benchmark for before and after.
Before the rewire: 45kbps
After : 52Kbps
The old wiring included some horrible DIY connections using normal flat non-solid telephone wire pushed into IDC connectors and wound around them.
