I have sand in my run, coop, and now our brooder. We love it! In the coop I use just enough to keep the poop from sticking to the floor. I scoop it every couple of days with a regular kitty litter scoop. Right now we have 8 hens and it takes me about 5 minutes to scoop it into a bucket which I then dump in our compost bin. It separates beautifully and any sand stuck to it is actually good for our compost because our soil is very heavy with clay. I also have a little kid's rake and smooth it out every now and then.
In the run I keep it a couple of inches thick. The girls love to scratch and take dust baths in it. It drains well, smooths out their feet and toenails, and is easier to rinse off boots. I don't scoop the run because the poop dries, breaks down, and disappears. The only time I scoop is when the girls are moulting and all the feathers pile up against the fence! The sand also gives them access to gravel for digestion (I use washed, all-purpose sand - not sandbox sand which is fine and doesn't drain well).
After experimenting with many kinds of bedding (paper towels, cloth diapers, doggie pads, paper litter, wood shavings, etc.) I decided to give the sand a try in our brooder this year. The baby chicks actually started dust bathing in it! I like that it doesn't end up in their water dish like shavings do, and it keeps their little feet clean so we're not getting smeared with poop every time we pick them up. The litter scoop doesn't work with their tiny poops, but a kid's sand sifter does for most of it. I've also noticed there's less odor with sand because the moisture is absorbed faster. It also retains heat from the heat lamp (think reptile tank). The little ones even nibble on the smaller pieces of sand allowing me to give them occasional treats without worrying about digestion issues.
For all areas, I replenish when it starts to look thin or muddy. I just pour the new sand on top and spread it around. Even though it's washed, it is still quite dusty, so I wear a bandana if I'm pouring a lot. I'm prone to allergies and the dust gets to me after a few bags.