What functions & features should I look for when buying a multimeter?

Question

Going to be used for car maintenance/restoration work and around the house repairs.

Answer 1

Core functionality of a multimeter:

Measures Voltage - the majority will cope here, as you typically are only dealing with 0 - 12 volts across most areas. You aren't going to need it to measure high tension things such as spark plugs, as you can check them using far simpler methods (such as a spark from engine block to removed spark plug)

Measures Current - currents in automotive circuits and audio circuits can be very high, so check your multimeter has a very high internal resistance and high current capability.

Measures Resistance - you'll probably find the most useful part of this is an audible continuity checker for checking cables deep in the bowels of your car

Frequency - less common on multimeters, but can be useful when working out speed/timing issues

Also make sure it is water resistant, and ideally comes in a rubber housing (as per @CodeBlend - Fluke are generally a robust and accurate brand to go for)

Anything more, and you're likely to need a computer with adapter and software to look at your ECU.

Answer 2

I know a couple of bits and pieces but not enough to recomend, here is a forum with some people that sound like they know thier stuf;

I hear Fluke meters are the business. But for 90% of people just go and drop $50 or something at a decent tool store.