When it comes to choosing between a 10-hole (diatonic) and a 24-hole (tremolo) harmonica, I'd recommend starting with a 10-hole diatonic harmonica. Here's why: Simplicity: A 10-hole diatonic harmonica is easier to learn because of its more straightforward layout. It's designed to play in a single key, which makes it ideal for beginners who are just getting started with the instrument. Versatility: While diatonic harmonicas are designed for a specific key, you can still play various music genres, such as blues, rock, country, and folk, by learning different techniques. Popularity: The 10-hole diatonic harmonica is the most common type and is widely used by both beginners and professional players. This means you'll find plenty of resources, such as lessons, tutorials, and song tabs, to help you learn. Portability: The compact size of a 10-hole harmonica makes it easy to carry around and practice anytime, anywhere. On the other hand, a 24-hole tremolo harmonica offers a different playing experience and is often used in traditional and folk music. It has a richer sound due to the presence of double reeds, but it may be more challenging for beginners to learn due to its more complex layout and additional techniques required. I recommend starting with a 10-hole diatonic harmonica for its simplicity, versatility, and abundance of learning resources. Once you're comfortable with the basics, you can always explore other types of harmonicas, like the 24-hole tremolo, to expand your musical horizons.