I board at a place that has a new owner who has never owned a barn before. The outdoor arena has not has a lot of attention and is getting deep in areas and hard on others. It has rubber and sand footing. As a general rule, how often do you drag your arenas? What conditions are best for dragging (ie wet, dry)? I want to give him the best advice on how to care for the footing he has.
I think, to a large degree, it depends on the amount of traffic.
With heavy traffic, it can be every day.
As for weather- it is heavy after rain and dusty in dry weather.
The place, I boarded, dragged approximately three times a week (with low to moderate traffic).
In addition, they always dragged before precipitation (rain) and after (if it was a heavy rain that “mutilated” surface; they dragged after it drained a bit).
Dragging is important so that the surface remains consistent all around. Furthermore, without proper care, horses eventually dig up the base, footing gets mixed, and the arena will lose its proper functioning.
So much depends on your environment, traffic, and footing type.
For me, I’ve got a coarse sand arena and it’s super wet and rainy around here this time of year. It’s just me, but the arena usually sees 4-5 rides a day. I’m stupidly anal about my footing and arena, so I drag 5-7 times a week, usually after riding everyone each day.
In the summer I drag whenever it rains. When we hit our normal 2-3 months with little to no rain, I drag once a month at most, and try to wait for it to coincide with rain.
I prefer to drag a damp arena (a “wet” arena just makes for a muddy/sandy dragee, and dry turns you into a dust magnet). On a side note, if you keep the arena dragged it will drain far better than an arena with footprints (another reason I drag so often this time of year).
At least once a week to keep the weeds down.
Indoor arena-I try to do it twice/wk but usually only manage once/wk. The only traffic in there are 2 retirees, usually individually, for about 15-20 minutes. Just enough time for a good roll and romp. After a good romp, both horses come right up to me as if to say, “Ok, I’m done.” 
Outdoor ring gets dragged a few times through the summer but it isn’t used anymore except for turn out in the early spring as it has a grass border so I can easily limit the startup time to grazing for my boys.
The barn we board at is relatively busy. Arena(s) get dragged at least once per day and more frequently during show weekends or when there is a need to do so.
