When Should I Stop/Start an IIS Application Pool?

I was told that every time I refresh our web site, either individual pages or the entire site, I should first stop the application pool, update my website file or files, then start the application pool. My web site files consists, of HTML, JS, ASPX, INC, GIF, JPEG, CONFIG, etcetera. I'm asking because I believe I have updated my site without stopping the application pool and starting it, and also by stopping and starting it, just trying to find out what the correct approach should be.

You don't have to recycle or re-start your application pool when you update your site. Neither for adding/updating files nor for updating your web.config.

IIS picks up all changes automatically.

Reasons for why you may want to recycle include:

• The application pool hangs and no longer serves requests.
• The application pool uses too much memory or your app has a memory leak.

By default an application pool is recycled every 29 hours, so usually you'll never have to recycle an app pool manually.

It really depends on what changes you're making. If you're just updating a config file then often you don't even need to recycle the app pool, let alone stopping and starting it. Whereas if you've changed some asp.net stuff, then recycling the app pool is usually required, but once again, a stop and start is not usually required.

Here is a good explanation of exactly what happens when you recycle an app pool and/or reset IIS. Give it a read and you should get a better understanding of when a stop/start is required.

http://fullsocrates.wordpress.com/2012/07/25/iisreset-vs-recycling-application-pools/