Programmers: When creating a mobile game application, how difficult is is to include a MUTE option?

I’ve noticed that those from from major game companies usually have an option to vary the sound levels within a game or to eliminate them entirely.

Many from smaller developers eliminate this option altogether. For others it’s all or nothing. It’s either sounds or mute, which I’m assuming saves a bit of work; but perhaps not.

Since I know nothing about computer coding, I’m trying to get an idea of how relatively difficult a simple MUTE option would be to implement (compared to the totality of work required for the entire rest of the game.)

I’m finding it so annoying particularly on games requiring thought (such as word anagram type games) to have all these extraneous sounds accompanying every move as well as repetitive background music.

Turning the sound off on my phone is equally annoying since it later affects phone calls.

So give me an idea of how much work I’m expecting from folks creating these games to just put in a simple MUTE option. I really don’t need variable sound levels: I’m quite happy with silence. How hard can it possibly be?

Please enlighten me.