Question on Tune Up Timing

https://raymondjjgf738.summitquill.com/posts/comfort-experts-on-refrigerant-leaks-and-ac-repair-for-north-fort-worth-systems

Question on Tune Up Timing Does anyone know if spring or fall is better for a tune-up? Not sure when it makes the most sense for an older system in Summerfields, since the AC works hardest in summer but the furnace matters in winter