Flash memory has a characteristic that, unlike RAM, you can only erase/write it so many times before it becomes unreliable. All flash parts will tell you what the write endurance of the part is.

If your flash part has an endurance of 10,000 writes and you'll be writing a value to flash every minute, that means your device will last 10,000 operational minutes... about a week.

A "walking write" is a strategy whereby you don't write the data to the same location in flash memory every time. For example, if you need to write 2 bytes to flash and your available flash is 1024 bytes, you write to a different set of 2 bytes each time. First at offset 0, then offset 2, etc. By doing this you increased your products endurance by 512 times (512 x 10,000 minutes instead of 10,000 minutes).

Of course this takes additional logic to determine where you've written the values in flash so you can find them when you read them and also to know where to next store the data on the next write. But this is a necessity if you'll be updating flash frequency.

If you won't be changing the values very often then it might not be necessary. Just keep in mind your part's write endurance and how often you'll be updating the values in flash. That will tell you if you need to use a walking write to make your flash last longer.

Regards,
Craig Steiner