All instruments work on the same musical principles and physical laws of vibration. Learning to play one can make the next easier to learn. Cross-training can further develop the possibilities and understanding of the first instrument. Finally, a passion for sound is remarkably hard to quench.
Pictured below: Guitar, Sitar, Sansula, Kalimba, Charango, Gong, Singing Bowls (metal and crystal), Tingsha, Drums (Ashiko, Djembe, Dumbek, Udu, Tabla), Jaw Harp, Didjeridoo, Native Flute, and Bowed Psaltry.