Do I need a sighting mirror on my compass?

Buying a compass can be confusing.  Do I get the el cheapo, the middle of the road, or top of the line, complete with clinometer and sighting mirror?

Doesn’t a mirror offer greater precision when taking a bearing?  The short answer:  Yes, it does, but for almost all backcountry uses of a compass, you do not need this level of precision.

If you’re doing field mapping or walking a straight line when on a search and rescue team, then the slight increased precision of a mirrored compass might be justified.  But for the vast majority of the simpler backcountry uses of a
compass, like taking a bearing to an object and then either following it or plotting the bearing on a map, the +/- 2 degrees of accuracy you can get with baseplate compass works just fine.

Also, consider that most mirrored compasses LACK most of these good qualities: 
Most mirror compasses: 

• do not have a long baseplate
• are not ergonomically designed
• are expensive
• are heavy
• have more moving parts that can break

I’ve used my Suunto M3 (without a mirror) compass to take a bearing from a map, follow that bearing cross country for more than a mile, and hit my precise objective . . . on a moonless night.  With a little practice, you can too.  Don’t throw away your mirror compass if you already have one and like it, but if you are looking for a compass to buy, the Suunto M3 or similar model is a better choice for most users.

The Suunto M3 is a recommended compass.  Read more about it here.