This is essentially the only cleanser I need to maintain my guitar.
Used on rosewood, the fretboard gets darker looks much "healthier".
Compared to other brand's products or complete sets of cleaning tools, it's reasonably priced and really does the job.
Make sure you DO NOT use it on a lacquered fretboard! You'll just get one big smeary mess.
It can also be used on metal parts like Bridge, Stop-Tail or Tuners and helps (to a great extent) to get rid of ugly tarnishing.
Preferably combined with a set of new strings, the guitar will get a better look, better smell, and most importantly: an overall fresh new feeling.
Really worth it and a standard supply.