I can say "Bob and I are going" instead of "I'm going and Bob is going." I want to say something like "This is a waste of my time and Bob's time," but only saying "time" once. I can't say "our" because I'm introducing the other person's name in this sentence. The best I can think of is "This is a waste of me and Bob's time," but that seems incorrect.
Bob's and my time
or (less common)
Bob's time and mine?
This is a waste of my time and Bob's
How about "This is a waste of my and Bob's time"?
This is a waste of time, both for Bob and myself