There's a misconception that keeps those with dreams of owning their own business from following their dreams. It's a misconception that's not only false but dangerous to the small business community. It's not true that every entrepreneur sits in a rundown apartment somewhere in Silicon Valley, eats boxes of cheap mac-and-cheese and stays up all night building the next big startup. Most entrepreneurs aren't living in poverty hoping to someday sign the papers for millions of dollars in funding only to see their dreams become the next worldwide craze.
The pros of starting a music lessons business as a side business are very similar to a foreign language business. Assuming you know how to play an instrument and enjoy teaching others, you have everything necessary to start giving lessons. Music lessons businesses are easy to run out of your own home, according to your own schedule, so doing it on the side will not hinder the success you may find.