Question on Tune Up Timing

https://andresetbt604.unionquill.com/posts/comfort-experts-new-ac-installation-for-north-fort-worth-homes-past-the-repair-stage

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