Tree growth is often overlooked as culprit for your solar underperforming over time. Installers may assume trees will not grow and/or you’ll keep them trimmed. There are even laws in some states ensuring your ‘right to sun access’ once you install solar on your roof, including from neighbors’ trees. Regardless of views on that legislation, it is a factor that’s often overlooked. Few people want to pay for a system inspection only to find out they need to pay someone else to trim their trees in order to restore system performance.