It takes long time to go through the process. Taking into consideration that they can spend a month or two with your application and then they will come with the answer “saying you don't have sufficient materials”, then you have to do it all over again. Many students whom I come across buy their tickets in advance, or wait until the last minute to file for a visa, and they will usually end up missing their flight or not being able to go altogether. Agencies are best way out.
If you have enough time and patience then you can go on your own on preparing supporting documents and processing visas through embassy. Because it will be a hectic process and will end up in making often to and fro trips. With there experience agencies can guide us through and time consuming also.
12 month multi entry tourist visa are all critical and complicated one and I would recommend you to seek a help of agencies.
