I'm currently a master student in the field of physics, so indeed it's not in US instead in Europe. Now I'm approaching the end of my master studies and planning to go to a PhD program. I have found more than one destinations (which exclude my own current university) which seem to suit my interest, so it's clear that I'm wanting to try my luck applying to all of them. Since one of the requirements is recommendation letters from former supervisor I would have to ask my thesis supervisor to provide the letters multiple times. My question is what do you think, will I cause trouble for him for asking to send letters several times? The thing is I come from Asian country in which there is a common manner that students will always try to keep formal attitude in front of lecturers, and doing such thing mentioned above will probably be considered as inconsiderate to older people. I don't really know how relation between students and lecturers goes in western countries since I have been here for only 1.5 years. In addition, as I have mentioned, I dont plan to stay in my current research group. So do you think my supervisor will be so professional so as not to feel disappointed over me and be willing to write the recommendation letters more than one? Also for you who have been admitted in PhD, did you also apply for more then one universities? Thanks in advance for your time to share your thoughts.