Do you need an id field on a table

Most tables that I have worked with in mySQL have an id field (or similary named) at the start which autoincrements with each post.

Although this is not necessary I wondered how common it is?

I have got into the habit of pretty much basically, no matter what db table I create, having an auto-increment id field at the start of the table... do other people do this or is it just me?

Re : Do you need an id field on a table

No you don't have to have an autoincrement field when working with a database table, but it can certainly be a useful thing to have and you will find this with many tables.