Whether the battery lasts all day or not, I think it's critical to have a backup of anything you can afford to have a backup of, in my opinion.
I considered a second 18650,but opted to get 2 of the 18490s instead.(not sure why),LOL,I had a budget of $220.00 for my purchase and got everything for $216.00 and change.So I guess I could have gotten 2 18650s and 1 18490.I guess my brain took a short nap somewhere in the process..

I was really,and I didnt not make myself clear,wondering if recharging the 18650 every evening would do it any harm,as Ive been reading about rotaing the batts and I pretty much will be using it everyday and using 1 18490 as a second batt to get me
thru the evening,and 1 18490 as a backup if the other two fail.I was thinking if the 18650 gets me from 6 am to 4pm,then Ill put it in the charger at that time each day regaurdless of the amount of remaining charge,as thats when I get back to the house(most days).And you are so very right.Back up, back up, back up,I have several 650mh eGo batts,reg,twists,and pass
thru.
I really hate getting senile.LOL,I had another question but forgot what it was while I was editing the top portion of this post.

I'll go make coffee and try to remember it...