Actually, I grew my hair out with weaves as well. I have had weaves in for 4 months or longer. The only thing I really worried about was shedding of the weave hair. Once I figured out the tricks, hair loss was minimal and matting/tangling was almost non-existant. My hair is natural--perms just seem to eat up my hair for some reason.
My weave routine below if anyone is interested:
1. There are only two stylists I will trust to do my weaves. If they aren't available, I don't let anybody do them.
2. Before getting the weave, I use a strong protein treatment like ApHogee Treatment for Damaged hair or Nexxus Emergencee followed by a moisturizer. I will either shampoo or condition wash the hair prior to the treatment and make sure I am washing my hair section by section.
3. During an experiment, I learned that for me, my stylist MUST braid up my hair in the tracks using SYNTHETIC HAIR, even though I don't need it for the braids, synthetic hair doesn't absorb oils or moisture very well. That is GOOD because the moisture and oils kept my hair slick and super-moist every time I washed my weave and oiled it. I figured out that was the very reason why the braids just fell out of my hair when I went to remove the weave. The weaving hair MUST be human hair.
3. When I have weaves in my hair, I have to wash and condition the hair left out twice as much as the hair locked in the braids--they hair of course dried at a faster rate. Hair locked into the braids (when I used synthetic hair) was already saturated.
Every head of hair is different, of course. I never experienced any problems weaving freshly relaxed hair back when I was using relaxers. Part of that may be the way the stylist braids the hair. When my hair was relaxed as a child, the stylist always plaited or cornrowed it right after she was done and I always had a thick head of hair. I also learned that the length of time for leaving a weave in my own hair didn't matter, it's what I did to my hair while it was in the weave that really made the difference---and of course a weave just does NOT look cute once you have about 1+ inch of new growth.