"Up to snuff," meaning "satisfactory" or "measuring up to the required standard" turns out to be quite an interesting phrase. First of all, "snuff" all by itself is an intriguing word, or should I say "words," because there are really two different "snuffs." The older "snuff," of unknown origin and dating back to the 14th century, meant the burnt part of a candle wick. As a verb, this "snuff" meant "to extinguish a candle" and it is from this sense that we get our modern metaphor of "snuffing" someone's hopes (or, in slang, actually expunging the person).
The other kind of "snuff," meaning powdered tobacco inhaled through the nostrils, came along a bit later, in the 1680's. The root of this "snuff" was probably the verb "to snuff," meaning to draw up into the nose (think back to your last "snuffling" head cold), and it apparently began as an abbreviation of the Dutch word "snuiftabak," or snuffing tobacco. "Taking snuff" was a popular habit in Europe for hundreds of years, so its not surprising that it showed up in a metaphor for "satisfactory" or "usual." What remains a little unclear about "up to snuff" is whether the phrase refers to a level of acceptable quality of snuff itself, or to the wide-awake and perky attitude of someone who has just taken snuff.
The phrase, "up to snuff," likely dates from Britain where it is recorded in 1811 with the meaning "knowing; not easily deceived". In America in 1831 its meaning had changed to "up to standard". The British meaning arose from the notion of being old or experienced enough to take snuff, and the American form was an expansion of that meaning.