Tools Needed: Cross-head screwdriver 

Parts Needed: Replacement bulb

Time taken: A minute - if that

You can usually tell when an indicator has gone (apart from looking obviously) as the relay and the light in the speedo will flash quicker than normal on the affected side.

If you want to change the lenses to clear ones simply swap with the existing, but remember to change the bulb for an orange one (available at any car parts shop).

If you're buying a new chrome top - don't buy anything Brazilian - it will rust within a month

Probably the easiest thing to do on a bug.
Earlier bugs had slimmer wing top indicators, but the procedure is the same.
Late bugs with the indicator in the bumpers are slightly different.

1. Make sure the ignition & light switch is off.
2. Using the screwdriver remove the screw that is located at the top of the indicator chrome cover
   
3. Remove the chrome cover and the indicator lense
4. Press the bulb down and twist to remove
5. Replace with new bulb and refit lense and chrome top, making sure they seat correctly into the rubber base 

Late model indicator in bumper -