Question on Tune Up Timing

https://connersuhm791.clarionvale.com/posts/repair-or-replace-your-ac-in-north-fort-worth-with-advice-from-comfort-experts

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