US Rubber Mulch provides the #1 safest playground surfacing for fall injury protection at the maximum testing height of 17 feet, drops above & below around 700 HIC, other rubber mulches get those great scores at drops of 10 to 12 foot heights. It won't deteriorate, so the same fall safety exists for the entire 25 years or more, and this is with a 6" installation depth. Top-off replenishment of 5% to 10% every 3-5 years is normal, depending on the number of children, use activity, and how many pieces make it home in little shoes and pockets. 

A playground of just under 2,800 square feet would take a truckload of 22 pallets, each one providing the required 6" thickness over 127sf, and it runs about $5 per square foot. Installation is quick, over the sub-base and drainage, and all you've got to do is occasionally rake it level and blow out the leaves and debris. The rubber mulch stays put, not bothered at all by heavy wind, or washed out with rainfall or run-off. 

Some playground have maintenance facilities and staff, where they blow out the leaves up to twice a week, and order a little extra rubber mulch to keep on hand to refresh it in a few years. Churning it helps to refresh the color without having to add anything, and using a wide landscape rake upside down works well (so it doesn't snag the geotextile fabric). This is also the best way to maintain the level, filling in low areas with the areas that have gotten thicker. It's normal to have a variance during playtime of +/- 2" to 3" in thickness, or kick-out effect, and the age(s) and number of children make a difference.