As for reference letters, I have come across distinct policies.
Some recommend to only give a reference letter for a particular application - it might be tailored to the particular position which the applicant soughts for.
Other do not seem to have a problem with providing generic reference letters. I personally prefer this one, because it is clearly less work for all parties involved.
So, which kind of reference is appropiate to ask for from your supervisor? Which one is socially accepted? (I am a former student that needs a letter of reference from his former professor).