My DJI GO APP is taking up nearly 3 gigs on my drive.  Once I have backed up my flight log should I be clearing my flight logs?  Is that what is taking up so much space. I have been clearing my videos and photos off the drive once I back up the card onto my computer.  Thanks!

Could you clarify what you mean by Drive?  Are you speaking of the storage space in your device,  or the storage on the Phantoms SD card?
The storage on your device does hold the flight logs,  which can consume space.  The storage on the Phantoms sd card is for photo and video.  Your device can also store low resolution photo and video, if set to do so.  The Phantom internal storage also carries flight logs that are not normally accessed by the user.