For the MCAT its really a personal decision.
Some people can't just focus on one thing and would need distractions.
Some people want it fast and hard and over. So they really cram for like 2 months and take it to get it over with.
Others can't do the cramming thing so they spread the studying out more and intermix it with their normal schedule.
You need to decide what works best for you. However, I will say in my experience as a teacher that the really long study plans and classes are usually a bad idea (eg class from Sept-April with fewer classes per week). Students usually can't stay focused on the MCAT because of their other classes, they don't keep up, get behind AND burnout.
For applications, I think it would be a little weird to completely take time off. Applications don't take up THAT much time.