I think that also depends on the country. In my experience, references don’t play such an important role in Germany as they do in UK/US. Especially the practice that referees have to submit their reference directly to the university is uncommon in Germany. Usually, referees would write a letter of reference for you, and then the applicant can hand it in. Also, having references tailored to the specific application (which seems to be expected in UK/US) is not common in Germany.
So, yes, I am also hesitant to ask my academic referees too often. If I knew that they would be contacted early in application processes, I would certainly apply for less positions. For example, I maybe wouldn’t apply for positions that I probably won’t get but would be great if they worked out.
I think that also depends on the country. In my experience, references don’t play such an important role in Germany as they do in UK/US. Especially the practice that referees have to submit their reference directly to the university is uncommon in Germany. Usually, referees would write a letter of reference for you, and then the applicant can hand it in. Also, having references tailored to the specific application (which seems to be expected in UK/US) is not common in Germany.
So, yes, I am also hesitant to ask my academic referees too often. If I knew that they would be contacted early in application processes, I would certainly apply for less positions. For example, I maybe wouldn’t apply for positions that I probably won’t get but would be great if they worked out.