There are many varieties of spark plugs on the market, each with its own set of benefits. Spark plugs can be made from a variety of materials, but silver, copper, platinum, and iridium spark plugs are some of the most common. Silver Spark Plugs are the most cost-effective option and can last for up to 20,000 miles before they need to be replaced. However, they don't hold up as well as other spark plugs and aren't a good choice for high-performance or heavy-duty vehicles. Copper Spark Plugs are a popular choice for many because these spark plugs work for up to 30,000 miles before needing spark plug replacement. Copper spark plugs perform well in most situations and are not highly-priced. Platinum Spark Plugs are more costly than silver or copper plugs, but they last longer, with a longevity of up to 60,000 miles. They can help you save money at the pump and are a great option for high-performance or heavy-duty use. Iridium Spark Plugs are the priciest option, but these spark plugs work the longest (up to 100,000 miles) and are therefore worth the extra money. They're built to last and can serve a variety of purposes with top-notch efficiency and performance. You won't find good spark plugs per cylinder than this.