Last year I had a 16GB memory card with about 10GB free space for Mapillary and high quality set which made it stop at around 14,000 images just after I crossed the South Australian border into Victoria (around 400km). I didn't realise it was on the high quality setting and not low quality. I missed out on a good 30,000 images (not more as I don't take images at night).
I now have a 64GB memory card so I could probably do 50,000 images or more before filling up. I went away last week and took around 16,000 images with plenty of space left plus I could move them to my laptop if I really needed too.
I have the 'show detailed stats' enabled from the developer menu which shows memory details when camera is selected.
If you set to have 'free storage limit' set to 0% it will have a hard stop limit at 50MB free space and will not continue to take any shots.
Memory isn't an issue for me at all my biggest bottleneck is upload speed as I'm lucky to get 600kbit out of a ~1Mbit service.