i find that a lot depends on the gear i'm using and it seems that every person is unique. 19-nor's, deca and tren, seem to be a lot harder to recover from than other aas. as for recovery of natural production, 2-3 months wont really make you certain of anything. the only way to really know is to find out what your base line test levels are before you cycle and then get tested again after to see if you have returned to that level. 

as far as getting a good effect from going back on, i do believe that if you were to take 3 months off, you would have given yourself enough of a break to go back on and get some good gains. to be honest though, i'm only guessing and over time, you'll eventually find that the same amount of gear wont take you as far as it once did. you get used to a certain dose, plus, if you're doing everything right, you go into the next cycle bigger than you had the previous, and that much closer or beyond your genetic potential