Depends on the horse, turnout situation and the size of the stall. When I had my last mare at home, she was in half the day and out the other half. Her stall was 12x24ā. I started out with a pickup bed of sawdust, which I topped with 4 bags of shavings. The sawdust was to prevent mud, since I didnāt have mats. I bedded the whole stall about 6" deep, which was about 3/4 sawdust 1/4 shavings.
She picked one end to lay down in, which was also the side where her food and water were. She pooped and peed at the other end, so it was fairly easy to keep clean and I didnāt really have to add much to it. As soiled bedding went to the manure pile, Iād move broken down but still good bedding to the other end and top up the bedding in the area where she liked to lay down with fresh shavings. I think I went through 2 bags per month in that situation.
When the same mare became injured and had to be on stall rest it was a whole different story. She would get agitated and pace, which ground everything up and made a horrible mess. I was going through 2-4 bags per week, just to keep the stall reasonably decent.
My current mare is at a boarding facility that uses the pellet bedding. She has a 12x12ā with an attached run and 8-12 hours of turnout per day. They used 4 bags of pellets to initially bed the stall, and just add as needed. Lily is a very tidy mare, and usually doesnāt make much of a mess in her stall. I think they add about a bag to a bag and a half per month.
Definitely do stall skins if possible, they are great! Mats are better than nothing, but they have to be installed on a level floor and be tight to each other to prevent stuff from getting under them.