My biggest has over 30 acres of turf. It's all cut up into smaller lawns all over the property.
It has a 3 spur rail yard that I keep the weeds out of. But they just paved it so it's just a matter of keeping the cracks clear of weeds.
My son and I will start mowing in the morning. He'll go one direction "trimming" with the 72" while I start the ball field & front lawn with the big mower. I'll not lay eyes on him but a couple of times before lunch, about the time we're finishing.
It's all fine cut mowing, we keep it at 3". There's a 10 acre field in back I sub out to a guy to keep it bush-hogged.
We apply fert & herbicides on the front lawns. It takes about 30 yards of mulch for the beds. Pruning shrubs takes us about 3 days.
This is my 30th year maintaining this property.
This isn't my biggest account, just the biggest in one place. We have several big accounts.