Problems with humidity can lead to heartbreak for the classical (or other) guitarist. Excessive humidity or dryness can ruin an instrument probably quicker than you think.

You must always be aware of what conditions you are leaving your instrument, whether inside a guitar case or within a room or in the open. They should NEVER be left in the sun for any length of time.

When guitars are built they are usually in an environment where the relative humidity of the room is kept constant, roughly around 50%.

To be safe you ideally should keep your instrument around this mark though they are generally regarded as safe between 40%-70% as the upper and lower margins. Below or above this can be drastic for your instrument!

An interesting example of anecdotal evidence of problems with humidity I've heard is with Ramirez guitars.

Because they're made in Spain where the humidity is often above the 50% mark and are shipped to areas where the humidity is much lower with dry winter conditions, they can easily develop cracks and slits throughout the guitar.

Having made an investment for such a beautiful guitar you