rough running on 1st start up of the day

I'll probably get flamed for saying this, oh well.

The carbs came on the engine new in 2015. The engine has 1200 hours. I personally have flown the last 850 hours. I fly the plane a RV-12, 3-4 days a week with 2 people and a dog typically cruising at 132 mph.  Using the fuel replaced method to measure, I get 4.3 GPH, 3.8 If I slow to 100. I feel if there were any issues with the engine or carbs my performance (I monitor it closely) would fluctuate. The carbs have never been "formally" overhauled. I replace parts as I notice wear. I use the mfg time line as a basis but not the bible. Carb balance is checked probably more often than necessary. I do subscribe to the "if it ain't broke don't fix it" ideology .... sorta.