Are there any common pitfalls or challenges to be aware of when implementing file downloads and uploads in PHP?

One common challenge when implementing file downloads and uploads in PHP is handling file size limitations. To address this, you can set the `upload_max_filesize` and `post_max_size` directives in your php.ini file to accommodate larger file uploads.

// Set maximum file upload size in php.ini
// upload_max_filesize = 20M
// post_max_size = 20M