Given that compass precision is a very relative thing, even more so for hand held models, I wouldn't worry about it. Magnetic declination can throw you off twenty degrees or more, twice that if you misremember the direction of the declination and apply the correction the wrong way.
A useful overview:
http://en.wikipedia.org/wiki/Magnetic_declinationDetermine the declination in your area:
http://www.magnetic-declination.com/Human error throws in a few more degrees plus or minus, and local conditions, like those magnetized brass plated steel buttons, are going to screw with accuracy even more.
The bad news is that using a hand-held compass, even with correction for declination, most people can't maintain anything closer than five degrees. But it doesn't make much practical difference because even though the readings are off they are fairly constant in their error. Local conditions, like that fire steel you keep in your breast pocket, are more worrying because they are far less consistent.
I have compasses that are thirty years old and have never taken any special care of them beyond not abusing the pivot by dropping them. They all still point well enough to use.
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