How long should I make database field to save useragent strings?
<p>I am customizing a login system and for security reasons have been asked to log all authentication requests.</p>

<p>One thing I plan to do is recording the incoming user agent strings and translating them when requested into displays such as <code>Request from: (Chrome/Windows)</code> or <code>Request from: (Firefox/Mac)</code></p>

<p>What length should my varchar field be in MySQL?</p>

<p>Do I need the entire useragent string to accurately determine the client's browser/os information in the future? Or is there some specification for useragents that allows me to extract only a substring from it and discard the rest of the "useless information".</p>