How much runtime do I actually need in a cordless vacuum?

Manufacturer runtime numbers (40-70 minutes) almost always refer to Eco mode with no powered brushroll. In real-world testing summarized by techradar.com on the Dyson V11 and rtings.com on Shark cordless models, expect roughly 10-20 minutes in the highest suction mode. For homes over 1,500 sq ft with carpet, look for swap-in battery designs like the Bissell PowerClean DualBrush.