External drives come in two varieties: HDD (hard disk drive) and SSD (solid-state drive). Both are great options, but each has its own strengths and weaknesses.
HDD external drives are the most common. They are widely available, affordable, offer a broad range of storage capacities, are available in both desktop and portable versions, and are well suited to storing large photo and document collections. Strength: Hard disk drives tend to be more affordable per GB and are often available in higher storage capacities. Potential weakness: HDD drives have moving parts that, when subjected to bumps and drops, can cause data corruption or loss.
SSD external drives are also widely available and are typically faster, more expensive and offer smaller storage capacities. Strengths: In addition to its speed, SSDs have no moving parts, making them extremely durable and portable. They are often available in significantly smaller enclosures compared to HDD options, so are ideal for on-the-go use. SSDs can consume less power and are much faster at accessing data. Many devices such as phones, tablets, and laptops use this type of storage. Potential weakness: SSD drives tend to be more expensive.