A:Answer That depends upon your transmitting source and environment more than anything else. Bluetooth (BT) was originally intended as a "PAN" (Personal Area Network), so the specifications have always been based on very low power signals (so they would be harder to intercept, among other things). Virtually all BT devices are designed for an operating range of roughly 10 UNOBSTRUCTED meters (32.5 feet) due to these specs. Some devices push these limits more, but rarely significantly so.
It's also sharing the same radio frequency range (2.4GHz) as many other devices (most notably WiFi) since it's one of the very few useful ranges that don't require an FCC license. There can be significant interference from those other devices - a potentially major problem in places with many devices competing to get their signal through (workspaces or warehouses with lots of BT devices, apartments with close neighbors all having WiFi and BT running, any public space with lots of people using BT like a gym, etc.).
TL;DR: I'd realistically expect roughly 20 feet (+/-5) in the average home environment. This goes for the vast majority of BT devices out there.
