Does a bathroom fan need an isolator?

Answer: No, never
Explanation: in most U.S. residential builds, a bathroom fan does not typically need an isolator switch. For a basic bathroom exhaust fan, no isolator is needed in but always follow local code and manufacturer instructions.

Answer: Yes, always
Explanation: it best for safety to have an isolator switch to insure safety and easy repairs

Answer: Yes, always
Explanation: It should have a separate switch for the fan and light

Answer: Not sure
Explanation: ?

Answer: In some cases
Explanation: The provision of isolating devices for extract fans in bathrooms or shower rooms is not specifically addressed in BS 7671. A fan isolator mounted adjacent to the fan would fulfill the requirement for switching off for mechanical maintenance. Regulation 537.3.2.2 requires the open position of the contacts of such a switch to be clearly indicated. Taking all of the above into consideration the following is therefore recommended: Extract fans having a ‘run-on’ timer: A BS EN 60947-3 fan isolator mounted adjacent to the fan would provide the appropriate means of switching off for mechanical maintenance. Where the isolator switches both the switch wire and permanent line conductor, this would also provide a means of local isolation where access to live parts is required. The isolator should be located adjacent to the fan outwith Zones 0, 1 and 2 in accordance with Section 701 of BS 7671:2008 (2015). The switch need not necessarily interrupt the neutral conductor.

Answer: Not sure
Explanation: Not required in my area.

Answer: In some cases
Explanation: It can be more than you need to get the job done - but then again I am not a licensed electrician and my area is in home remodeling. I always consult with a professional electrician and defer to their expert advice.