Project render files

Didn't realise that these got so big I thought all the renders files were kept in the Events folder. What is everyone doing regarding the project render files. I ask because I have chose to keep the projects folder on my system drive for easy backup purposes.
I see the option in the menu bar to delete project render files, is it just a case of keeping an eye on these render files and delete if the system is slowing up??

I apologise if this is going over old ground:-)

Yes when I realized this too I changed my methodology.
I now have a drive for projects and digital assets and drives for Events.
If I'm doing a new version of a project I delete the render files of the old one.

Without knowing specific scenarios I bet this is why people are experiencing FCPX slowing down its because the Project render files are hogging the system disk.
Might see how I go with this as I build up projects and see if it does affect the system.

Thanks

Your final cut projects and events folders should not be on the system disk. They are created there by default but you can place them anywhere or on any drive so long as they are at the root directory.
Accessing project files while your system needs that drive for the OS and apps is a bad idea. Move those folders off the system drive and you'll have a much better experience.

I only had the Projects folder on my system drive because it was easier to incrementally backup via SuperDuper. I have only just come across the fact that there are big render files in the projects folder. I just assumed that the media render files were only present in the Events folder (with the Media) Like Seanus has also mentioned I to will rethink how I organise my folder structure now.
I do know about what you have mentioned just didn't realise about the render files!

Thanks