Do you use a tool to generate sitemap on every site update?

Do you use a script to automatically generate your sitemap whenever your website is updated?
If so, is there a good script out there to use?

 

I just do it once in a while. But it is easy to automate most scripts / programs to run e.g. once-a-day (using e.g. Windows builtin functionality for this)

 

I use a php script on all of my sites and set it up do to it automatically with a cron job.