I'll tell you now. Enhancing without Cash Shop is a baaaad idea (especially on T2 and T3). And if you want the breakage rate on enhancement, here it is:
T1: approx. 2.5644/10 tries will break until +9 is achieved. (80.5466% chance of
not breaking all the way to +9).
T2: approx. 4.4869/10 tries will break until +9 is achieved. (60.6241% chance of
not breaking all the way to +9).
T3: approx. 7.1596/10 tries will break until +9 is achieved. (30.9514% chance of
not breaking all the way to +9).
*Note: The master of my guild got these percents based on 5 different 1H Swords of each tier. However, I do not know if the % rates differentiate between servers.
*Also note, that there is an even higher chance of an enhanced item degrading when enhancing. Just to give you an idea, to get a lv. 60 Sword (or any weapon) from +0 - +9, based on stats, will take you approx. 467 new Swords until you reach +9!! FAIL. x_x
Hope I helped!!