Whether you format or not, you do need to pull the card and check it occasionally as no cam can detect and warn you of every kind of card error. I always view the vids of the first, last, and some in-between files on the card at least bi-monthly and preferably monthly. Also if there has seemed to be any anomalous operation of the cam at all. Look too at the file sizes; except for the 'closing' files they should be roughly the same size. I always format my cards after doing a 'check-up' first in PC then in-cam, as that seems to keeps things running smoothly. It really doesn't work the card much to format it.
The usual simple or quick formatting does not actually erase or remove any recording files from the card; what it does do is
erase the file-name data on the card's file system which prevents finding those files through the usual means, so that the PC and cam now "see" an empty card
which is actually still full. Only doing a full-formatting actually erases your vid files, which
does work the entire card instead of just a tiny part of it. One "caveat" here is that MAC systems are notorious for inserting hidden files onto your drives, which includes SD cards plugged into a MAC computer. Those files can cause anomalous cam operation so
anytime your card goes into a MAC device you should format it in-cam before driving again
As always, the best advice is to do exactly what the manufacturer says to do. But do at least periodically check your recordings so you can know for certain that your card is still good and that the cam is still recording and closing files correctly
Phil