If you find that your bathroom mirrors are getting too dirty too fast, don't worry. There are easy ways that you can keep your mirrors cleaner on a regular basis. First, figure out what is causing the problem. Are you using hair products such as sprays that may be spreading a residue on the mirror? Does your make-up stray from the case to your face and end up on the glass? If you can properly address the main problem, you will take a big step forward in the process.
To keep your mirrors cleaner on a regular basis, you should first give them a really good cleaning with a typical glass cleaner. After you are done with that, apply a streak free mirror cleaner to the glass. Even RainX now makes a product for keep mirrors cleaner and free from fog. Fog from a shower leads to many streaky and dirty mirrors and these compounds can help a good amount.
Once you have these things taken care of, regular wiping of your mirrors should be sufficient to keeping them clean. If you have an older mirror that you can't seem to get clean, there may be imperfections in it from the age and you should look into replacing it.