Does the Roomba j7+'s runtime matter if it self-empties?

Regarding the Roomba: No, because the j7+ runs about 75 minutes per charge — enough to cover a main floor — and when it gets low, it returns to its self-emptying base, recharges, and resumes automatically. The bin fills for weeks before you need to swap the bag, so runtime becomes irrelevant. If you have stairs, it’ll need a mid-session charge, but the resume feature makes that painless.