Why should I always use UTF-8?
UTF-8 has some great advantages, it contains all special characters, and at the same time, it is compatible with "old school" characters (below character code 128).We live in a multicultural world, with a lot of specialized characters, but most of the world, uses standard characters from the English speaking world.
UTF-8 characters consist of one byte, when the character code is below 128, and of two (or more) bytes, if the character code is or above 128.
Since most text on the Internet is written in standard English characters, the size of a UTF-8 document is almost the same, as a standard ASCII document, and it still has support for special characters.
The UTF-8 character set, is a true expansion of the ASCII character set, and therefore documents in ASCII format, does not need conversion.