How many spark plugs does a Honda CR-V need?
Even if only one spark plug is found to be faulty, they should always be replaced in sets. Most engines will require 4,6, or 8 spark plugs. via
Which spark plugs are best for my car?
Iridium is said to be six times harder and eight times stronger than platinum with a 700° higher melting point. Iridium spark plugs have extremely fine electrodes while retaining excellent wear characteristics. Thanks to its strength, iridium spark plugs can last up to 25% longer than comparable platinum spark plugs. via