A single cosmetic panel on a sectional door is one of the more DIY-friendly garage door jobs, and with a newer 2004-era door the hardware is usually in good enough shape that swapping one section doesn't turn into a hinge or roller project too. If you're comfortable disconnecting the opener, supporting the door, and working around spring tension, a bottom or middle panel swap is within reach for a handy homeowner. Where it gets harder is matching insulation type and R-value to the rest of the door, and getting hinge alignment right across a wide double door so the new panel doesn't bind on the track. We're honest that we'd rather quote you a panel-only job than talk you into a full door replacement you don't need - replacement only makes sense when the damage has spread past one or two sections or the track's bent along with it.