OK, my answer might not be the one you want to hear, but I know from experience that the only thing that has helped me keep my hair in spite of all the years I've worn braids 24/7, is making it a mission not to let any braid dangle loosely at the base, particularly along the perimeter of your hair. Now that's not something easy to follow if you are not doing your own braids, because it may mean getting them redone every week. But that's the best advice I can give you.
The next best advice I can give you, if you aren't able to keep re-touching your braids to keep them neat and firm at the base, is to follow the braid regimen on
www.growafrohairlong.com Now I don't know what you mean by micros--since the word means different things to different people--but Robin doesn't encourage wearing very small braids, and so if you didn't follow that piece of advice, I'd say get them redone as soon as you can afford to, and then follow Robin's directions to a T, and you'll have less chance of experiencing damage.
Anyone who's worn extension braids for long and is happy with them will tell you that how long one can keep them really depends on the person: how long the hair grows, how well they were done (if carelessly done they'll come out anyway), how bad they look (you wouldn't keep a messy head just to keep it), how you feel (if they're too tight and hurt, they must come out ASAP, or if you're getting headaches).... The list is endless. Anyone new to extension braids should not follow any other regimen but Robin's Crown and Glory, IMO.