I am applying for several large scholarships that require one or two teacher recommendations. Rather than asking all the teachers that consider me one of their best students for a new recommendation every time I apply for a different scholarship, I thought it would be more convenient if I asked one teacher to write me a recommendation letter that he/she would save and use when the following scholarship applications came up, sort of like a template. As only one of my teachers is nice enough and has enough free time, I would still ask various teachers to be the second teacher to recommend me. There are, however, two problems that might occur: (1) the scholarships might require a different format for the letter, causing the teacher to spend time altering the template letter, (2) it might make the teacher think that I am ungrateful for his/her help. Please tell me what I should do (and why) or if I am not considering other factors. Thank you in advance for your mature advice.