How often should I shampoo AND/OR condition? (SUPER tangly hair)?

Recently my hair-wash routine was: daily, I would shampoo then rinse, then comb in conditioner and rinse that. But I've been reading that I don't need to wash my hair every day. So today I skipped shampooing altogether and I was going to skip conditioning but when I combed it in the shower, I COULDN'T comb it. The comb just got stuck in my hair. So I put in conditioner, but I did something different--I put it in the strands and left none for the roots. So should I shampoo every other day, and keep conditioning every day? My hair combed easier when I didn't put any conditioner in the roots. I'm not sure why, I'm guessing it was because when I put it in the roots there wasn't enough left over for the strands. It's not that I don't like the way my hair looks (I do), but I hate the combing so much that I dread it, because it's so painful and I lose so much hair every time I comb it, so I was wondering if there was another way. I don't know if my hair was greasy because I don't wash it enough, I wash it too much, it's naturally that way or just because of the heat/humidity.

If it helps: My hair is naturally blonde, very thin/fine, and also very long. Without any styling products, it is slightly wavy/gently curly. I used to use heat to straighten it but I don't do that anymore. It has never been tightly curled. I live in Chicago, and although we're more famous for our cold, we get just as hot and humid as Florida during the summer.