The announcement for a position I am applying to says "two recommendation letters must be sent directly from reviewers".
While I have reviewers that could send good recommendations for me, I find to be impolite for me to ask them to prepare documents, send somewhere, and this is for just one more application that is even before the stage of passing preliminary selection.
Writing a decent letter of recommendation would probably require no less than 20 - 30 minutes for them, even if they have done it once five years ago (I have old signed copies I could provide instead). These my former supervisors are of obviously busy people. There is probably limited number of times before my former supervisors could do this for me before going out of temper. I could contact them and ask to send letters after I know I am considered for the position seriously enough.
What is the right phrasing to explain this? Would it be understood?