A useful solar payback period checklist should include the system’s total installed cost, eligible government incentives, expected annual generation and your current electricity rates. Check how much solar you are likely to use yourself versus export, along with feed-in tariff assumptions, seasonal usage and any plans to change household consumption. For a battery, include its extra cost, usable capacity, efficiency, warranty and likely replacement needs. Allow for panel degradation, monitoring, maintenance and possible electricity price changes, then compare estimates from reputable installers. Actual payback will depend on your circumstances and should be confirmed using current information from the installer and energy.gov.au.