I've only been playing a month and the file usage is over 50mb. At that rate, it's over half a gigabyte for ten months. The log files are to help BSG find issues. I'm not sure if they're automatically sent to them or if they request them for issues. If someone knows, I'm curious what they ask for.
Under your install directory, there is a Logs directory. You can safely delete all the sub-folders to clean it out. Prior to deleting them, you can right-click on your Logs directory and click on properties to see how much space is taken on your hard drive.
BSG should probably auto-clean these directories for us with the launcher, if they're older than the current patch.
TLDR: If you launch the Tarkov installer, you can click on the down arrow under your profile name and click on "Logs". A Windows Explorer will open with all your logs. Those are the files you can delete.
