If a person cleans the rails out on thier saw bar with a horse shoe nail or some other thin pointy piece if metal every time he takes his chain off when swapping out chains. The tip should be getting plenty of bar oil for lubrication. Especially if the oiler's suction valve is opened all the way up!
If you are hand filing and not swapping out ground chains. Then the rails should be cleaned out at the end of every work day or every eight hours. I've never greased a saw tip and they most often last the life span of the bar with just the bar oil fir lube. However. They only last if you religiously clean the rails out at the end of every work day or chain swap!
Cut safe, stay sharp, and be aware!