Ask whether the installer is currently accredited with Solar Accreditation Australia, who will perform the electrical work, and whether they hold the required state or territory licences. Compare the system design, panel and inverter warranties, workmanship cover, estimated output, payment terms and any ongoing monitoring or maintenance costs. Confirm who will manage grid-connection paperwork and whether the quote includes all likely extra charges, such as switchboard upgrades or roof work. Check the installer’s reviews and business details, and have a licensed professional explain anything you do not understand before signing.