I did 2 and occasionally 3 activities a day (flight, sim, or discussion) when working on my IFR, and it was beneficial to me. The pace was quick, I studied between slots, and am glad I did. Occasionally our students have doubles (4 year degree 141 program), but only if they either request it or have no other availability during the week (because flight is a course with college credit, they have to set aside a certain amount of time).