How long should I wait to dye my hair so it wont fry?

It's supposed to be 3 months or more in between dyes. But the ones that wash out aren't as bad. Especially if they have natural ingredients and no ammonia. Lately I've been dying my hair a lot with permanent stuff and I now have a lot of flyaways and it's very course on the top. But I've been conditioning and it's helping to make it smooth, soft, and healthy again. So just be sure you're careful!