Why not to use Magic Quotes

• Portability Assuming it to be on, or off, affects portability. Use get_magic_quotes_gpc to check for this, and code accordingly.
• Performance Because not every piece of escaped data is inserted into a database, there is a performance loss for escaping all this data. Simply calling on the escaping functions (like addslashes) at runtime is more efficient. Although php.ini-development enables these directives by default, php.ini-production disables it. This recommendation is mainly due to performance reasons.
• Inconvenience Because not all data needs escaping, it's often annoying to see escaped data where it shouldn't be. For example, emailing from a form, and seeing a bunch of \' within the email. To fix, this may require excessive use of stripslashes.