Here's a screenshot of the memory card format settings. Whether you choose type A, B, or C is what will determine how much video is saved before it gets recorded over, and at the bottom you can choose to have certain video types never be overwritten.
The bottom screen are my settings, which with my 64Gb memory card sets aside 34Gb for continuous (driving) recording. I also unchecked the Incident recordings in continuous mode, so if I'm in a crash and for whatever reason the dashcam continues to record the crash footage will never be erased. Although, I believe the F770 has an internal memory card that saves a copy of crash incidents, so I'm not sure if I really need to do that.
So how much time you have really depends on how you choose to setup your recordings, once you know that then you can do the math and get a rough estimate. The F770 records in 1 minute intervals with each about 80Mb in size, and since I'm using Type C, with 53.6% dedicated to continuous recording that roughly translates into 428 minutes. (64Gb * 53.6% = 34.3Gb for cont. rec., 34.3Gb, or 34304Mb divided by 80 Mb = 428 minutes, or about 7 hours.
I think I did my math right, I just know when I review footage I usually only see stuff from a few days ago.
While on the subject does anybody know how to edit the 1 minute videos together, or even better include the rear cam footage overlayed on the front cam footage? I naively assumed the Thinkware software would provide basic video editing tools, but it doesn't. Kinda curious how Blackvue's software compares, because personally I think Thinkware's PC and Android apps are garbage.