The time it takes

I know that everyone's body is different, but I was wondering how long it usually takes people to gain weight.  How long of a road am I looking at?

I am 5'8" and I weigh 106 lbs.

I was also wondering how often I should be increasing my calories.

I weight myself everyday. For the last three weeks, my has ranged from 105-107 lbs.  I had increased my calories by about 200 calories a day and it didn't really seem to make a difference.

Thanks for any insight anyone might be able to share!!