I’ve used the same plug for over a year on a bike before. Keep the gap set and you’ll be fine. As the electrode wears it will become rounded and you will loose some performance but I’m not savvy enough to notice it.
Since the ES plugs are so cheap I usually put a new one in when I do a top end job whether it needs one or not.
I only ride in the woods etc, and only change my plug if:
1) I check it and it's quite dirty (sometimes even then I just clean re-gap and wash it with gas)
2) Feel a power loss after I have been chuggging around in tight woods.:D