There's a lot of factors on how often and how much water to give. Personally, I add perlite to my fox farm O.F. and so there's less moisture retention than if I was using straight up OF. Start off with evenly moist soil mix, if it's dryed out, use something else.
I disagree about it being that black and white in regards to letting it dry out. You should give your plants a deep watering and try to avoid totally drying out the soil because that will create preferrential channeling and you'll have a hard time evenly soaking entire rootball, which also causes ph problems. By nature, overwatering isn't what hurts the plants, its the lack of oxygen the water causes.
Case and point: in my learning stage of growing, I've pulled the dirt ball out of the container and noticed entire dry patches midway and in the lower area in the soil, but when I altered my watering habbits to include more thorough watering, my plants' health improved, instead of losing leaves prematurely.
All of this you must factor the size of your container versus the size of the plant, I tend to keep them in smaller containers, two gallon for closet growing. If you're vegging small plants in five gallon buckets, watering can be tricky. Another thing to remember is to keep the water warm, or heat it up in the microwave a bit if you just have a few plants. i found a spot on my floor in the kitchen hot water goes under, and after a day sitting there, my five gallon water jug is nice and toasty warm.