Lighter strings are usually found in gauges 8 and 9 but can sometimes be found as low as 7. Thinner strings mean thinner tone but the string will be more responsive to your fingers. This provides you with greater freedom to move across the fret board. The lower string tension will be less uncomfortable for new guitar players. However, lighter strings are weaker and more likely to snap.
Higher gauges provide a much fuller tone and higher volume for your guitar but have much higher string tension. This makes fast fretting, bends and complex lead playing more challenging and can be painful for a beginner. High gauges such as 11 and 12 are ideal for heavy, chunky rhythm playing and loud chord strumming.
Most major guitar manufacturers offer a range of custom string sets that allow you to combine higher and lower gauges to tailor your sound to your preference. These will most commonly have higher gauge on the lower strings for rhythm and lighter higher strings for lead.
Changing gauges may also require an adjustment of your guitar to counter the difference in string tension. A drop to a low gauge may cause fret buzzing as the lower tension allows the string more space to move. A simple bridge or truss rod adjustment can solve this.
Phosphor bronze strings are composed of 92 percent copper with 8 percent tin added to improve sustain and retain tone for longer. Nickel wound strings are wound with steel electroplated with nickel. This is designed to give a better response to magnetic pick-ups. The nickel will reduce string corrosion. Stainless steel strings consist of a steel alloy with added chrome and nickel to give a bright tone. The durability of the stainless steel will also help to reduce fret wear.