Thanks for bringing up the issue of vacation leave and duty leave. The current guideline is to give only vacation leave for all visits including conference visits during May 1st to July 31st. In the steady state, this works out better for you: Suppose x is the number of days of your vacation leave (given for conference visits). This does reduce your earned leave by x/3. However, it will preserve for you x days of duty leave. Please note that there is an upper limit of 180 days of duty leave that you can avail over a rolling period of seven years. I don’t want to get into more details, please do go through the leave rules, a copy of which you would have got as a part of your offer letter. Some of you were asking about where to find the leave rules. Please look up on the IISc website the following link:
Also, vacation leave facility is a very nice, somewhat unique aspect of the IISc system; even if you are away for all the three months of the vacation, you will only lose 30 days of earned leave. If you go through the rules governing earned leave, you will realize why this is such a nice facility.