There are 3 things to consider when getting guitar strings: String gauge, material, and brand.
String gauge - The most common guitar string size is .010 - .046. The .010 string is the smallest, and the .046 string the largest. The next most popular size is .090 - .042. Naturally because the strings are smaller it creates a bit of ease to play because there is decreased tension. .090 - .042 is recommended for those with sensitive fingers and/or beginners. Naturally if you want to bend strings more this is your gauge, but the heavier the strings, the more “full” or “supported” they sound. It’s about finding a good blend between functionality and tone.
Material – Most strings are made of steel, but the real difference lays in the wound material around it. Some strings are nickel plated, some copper plated, some even tin plated. All materials have different advantages. For example, nickel plated sounds balanced between snappy and smooth, but stainless steel is snappier and brighter. All depends on the tone that you want.
Brand – Even with brands that offer the same gauge or material they may sound a bit different. This is where personal preference and experimentation come in handy. I personally don’t REALLY mind different brands, but if you’re a serious player, it may be something to consider.
I personally don’t like anything smaller .010 - .046. I think it is a perfect balance of tone and ease. If you’re just starting out a size smaller may come in handy, but I think your fingers can get used to it quickly. However as stated previously, it’s all personal preference.
That being said, try them out! See what you like best!
BUY WITH CONFIDENCE