What do you use to control them, and how often do you have to apply it?
To whom?
The lawn. 
Sorry, can’t help. I have three dogs who get flea preventative, but I don’t have a lawn.
When I first moved into my current house, I had an astonishing tick infestation (the previous owners had outside dogs, and never took car of their ticks). I used a hose-end sprayer and an Ortho Tick control pesticide to spray all around the house, and that took care of them. I’ve never had to re-spray. I try to avoid insecticides - that’s the only time I’ve ever used a blanket spray.
Out here in the sticks we use guinea hens. If you live in town or suburbia though, the cure could be worse than the infestation. Damn things are noisy!
I’ve thought about them. I have many worries, including if they would tear up my carnivorous plants to get at the captured bugs.
How to they know where they live?
How do you provide for them in the Winter?
I’m worried that they would wander too far to the North and get hit by a car, or too far South and be shot for a quail or pheasant.
Have you lost any to West Nile ?
Don’t know, I have my garden area fenced, but they don’t seem to bother the flower beds scattered around, other than scratching around them. I think as long as they can find bugs they are content.
Don’t worry, unless your neighbors feed them, they’ll know exactly where home is and let you loudly know when they are out of feed. I just feed them chicken scratch.
They do wander, a lot! But you’ll know right where they are if you listen.
Here, they have a fancy chicken house to live in, but unless it’s 20 below, they prefer to live in the trees.
They are pretty savy birds, so you won’t lose too many to predators or cars, but if you do, you’ll be thanking your lucky stars.