Manual wheelchair users experience significant physical strain on the upper extremities, in part due to inefficient propulsion and frequent braking for directional control. This study investigates the real-life applicability of an upper-body-actuated wheelchair steering system, “steering-by-leaning”. Four experienced wheelchair users tested a prototype in daily life over multiple days, followed by a controlled trial, comparing conventional and steering-by-leaning mode. Results indicate that the steering system reduces physical effort, increases movement efficiency, and allows for higher velocities while decreasing braking energy. The study confirms preliminary laboratory findings and highlights the need for individual wheelchair customization to maximize benefits. These insights contribute to the development of more ergonomic and efficient assistive technologies, aiming to reduce barriers in place for wheelchair users.