The answer to 'when to replace tune-up' is that HVAC systems typically need a tune-up every 1-2 years, depending on usage and environmental factors. Regular tune-ups help ensure your system is running efficiently and can extend its lifespan. However, there are some signs that indicate it may be time to replace your tune-up rather than just perform another routine maintenance.
If your system is over 10 years old, it may be more cost-effective to replace the entire unit rather than continuing to invest in tune-ups. Additionally, if you're noticing higher energy bills, uneven heating/cooling, or more frequent breakdowns, those are signs that your system is reaching the end of its useful life and a replacement may be necessary.