Nice idea or not (I wouldnt need that feature): its not good to fill the card to the end. This can cause trouble.
I would change my 32gb card when there are only 50 left from the apr. 1000 possible files.
My 2€- cents.
1D MKIV, 1DX MkII, 5D Mk IV; lot of lenses, flashes etc
Fuji X100s, Sony RX100 III,
Fuji X- XT1, X- Pro2, XF 23 1,4, XF 18- 55 2,8-4, X- T1, XF 16/1,4, XF 55- 200, XF 56/1,2, XF 50-140, XF 100- 400