I've had locs since 03. I try to go 2 months at the least between wash and retwisting. I am extremely tender headed and I try to stave off a retwist as long as possible. I also feel ( no proof) that frequent and tiiiight twisting leads to loss of hairline or baldness. I have to keep my hair neat since I go so long between twisting. When I started I had my dreads twisted very thin, and as the years have passed I have doubled, trippled, the size of my locs by twisting them onto each other. My dreads were so thin initially, that they still look good now.
Here is my advise, if you already have started, go to your fabric store and go to the remnant section, and buy a large sheet of lycra or a lycra type material. It is stretchy and allows the hair to be tied down without frizzing. I cut them into strips. When I put it on, I tie it like a do rag, but I make sure I have it over my eyes when I tie it down. Then after it is tied, I just fold it up. This allows it to stay on your head even as you sleep.
I also tie my hair down when not in public. I tie my hair down as soon as I get home. If I am playing ball, going to the gym, even walking around the house. This stops my hair from being frizzy. I just use regular gel from Walmart or wherever that has the strongest hold and that is anti-flaking. I don't get a line up anymore, I have no need-gotta protect that hairline. And lastly, I don't have them twisted as tight as I used to. Hope this helps.