Hi Naz,
I whole-heartedly support your efforts to try to find relief from your allergies and your willingness to invest the time and money. I went through allergy shots twice, each time for a period of about three years. However, I don't think this is common. But I have very severe allergies, including top of the charts mold allergy, and I was living in a moldy house at the time. Talk about stacking the deck against me. Don't worry, it's usually less time than that. After the first round, I got so much better I no longer needed medication or an asthma inhaler as I also had allergy-induced asthma. But after awhile, I began to develop symptoms again probably because I didn't move. Keep in mind I was still living in the moldy house. I started the second round and after so much time, eventually grew tired of the whole process. But the results were great. It's been about 7 years now and I seldom use allergy medication and never use an asthma inhaler. And by the way, I moved into a mold-free house. So it was a success! You should do great and be done in a lot less time as long as you aren't doing things like me to undermine the effort.