What is a good size (in bytes) for a log file?

I am using the python logging modules RotatingFileHandler, and you can set the maximum size of each log file. What is a good maximum size for a log file? Please give your answer in bytes.

My default logging setup:

RotatingFileHandler(filename, maxBytes=10*1024*1024, backupCount=5)

As the other answers have said, there is a no hard and fast answer. It depends so much on your app and your environment. Here's some guidelines I use.

For a multi-user app on a typical server: Configure your logging to generate no more than 1 or 2 entries per user action for production, and then rotate it daily. Keep as many days as you have disk space for, or your data retention/privacy policies allow for. If you want auditing, you probably want a separate solution.

For a single-user app: Try and keep enough information to diagnose anything weird that might happen. No more than 2 or 3 entries per user action though, unless you are doing batch operations. Don't put more than 2MB in a file, so the user can email it you. Don't keep more than 50MB of logs, because it's probably not your space you are wasting here.