How to tell supervisor too many lengthy meetings are hurting your productivity? My supervisor wants us to meet 3-5 times in a week with another PhD student of his. Every meeting is on average more than couple of hours. I don't know about the other student. But I feel like we are wasting too much time in meeting; it's hurting my productivity. How can I tell my supervisor to keep the amount of meetings and duration limited? To make matter worse, he also wants us (me and other PhD student) to meet separately besides these meetings. I am spending on avg. 12-15 hours per week doing these meetings.

I can answer questions why I think these meetings aren't productive, but that may turn into rant and I may put them into another question. So I want to keep it short and precise; let's just assume these meetings aren't productive for me.
I think this is a time to be direct and honest: just say you are spending too much time in meetings and it should be reduced.  Say what you should be doing instead.  A reasonable person should not be offended and should know that meetings can hurt productivity.

I also recommend considering changing the way the meeting works to align it with your needs.  When I am in a meeting, if nobody is taking charge, I will try to be a leader and give the meeting some direction.  Remind participants of the agenda.  Add the things you want to do to the agenda.  But be tactful.