New running plan

I think I figured out why my running seems to screw my legs up all the time. I go a week at 3 3-mile runs. I have no pain, so I'm like "OK all's well, let's start increasing by 10% next week". Then next week I run an extra mile and screw my legs up. I'm going to try to run 3 weeks at 3 3-milers and see how that feels. If that goes well, THEN I'll increase the milage. I never give myself a chance to see if I truly was pain free after a 3 3-miler week because I immediately start increasing milage.