I recently got my At700 Strung with Bg80 @ 23 lbs... I was wondering, how much tension will the string lose (In 2-3 months)??
In short, quite a lot. BG-80 is reasonably durable and long-lived (in comparison to most other strings I have used). I should imagine that it will be below 20Lbs in 2-3 months but I could be wrong. Really, it's gonna depend on how often you play and how hard you hit.
I play around 3 hrs a week and i have an okay smash, but since I play doubles i tend to hit hard alot...But i heard most people say that it lowers 1-3 lbs then it stables abit. Is that true?
Yeah, there's some truth in that. You'll find that it drops quite sharply but then the tension sort of levels (still goes down but much slower than before). If you only play for 12 hours a month, I'd say keeping strings for about 1-2 months would be fine. There isn't much chance of them breaking at that tension either. Mis-hits reduce string life too so keep that in mind.
Either on the very edges of the string-bed (as in the first or last cross or main) or on the frame. Amongst good players they are rare but beginners make them regularly. This is another reason beginners shouldn't use high tensions (too many breakages of rackets and strings).
Unless the stringer did a bad job, or temperature change a lot, or you are a very hard hitter (but that will usually break the string, rather than losing tension), it should not drop 3+ lbs in 2+ months. In Yonex range, BG80 holds tension fairly well, especially if the stringer has a consistent pulling machine, and knows what s/he is doing. Usually, within the 1st week or so, the tension may drop 5-10% depends on all the factors. Afterward, it should slow down significantly. If somehow you can have the string for over 1 year (which might not be a good thing), it maybe less than 20, but i still doubt it.
Mis-hit usually means the shuttle struck the string bed way far away from the sweet spot. The stroke is not solid, and might even have some weired flying pattern. Your hand can definitely send a signal to your head to inform that.