Robot vacuum handling of battery life/maintenance

I dont understand what you are saying. My vac runs down so low that very occasionally it will have to go charge and then return to finish. But I have my rooms all broken out to allow an hour of cleaning roughly and the vacuum completes the areas and returns to charge without issue, sometimes the battery is very low but never completely out. I dont just let my vacuum do a whole house clean as it would never do it in one shot. Is that what you are talking about? In a nutshell I clean 2, 3 rooms at a time… several times a week. My carpets have never been cleaner.