Having good EC's is not doing one at the expense of the other. Most medical schools expect you to have them all, meaning that they expect some leadership experience, exposure to what medicine will entail, and something that you do for fun aside from going to school and that you have done this for some time. It is not about hours per se spent doing each EC, it is about how long did you engage in X or Y EC long term. It is too easy to volunteer for one summer at 40 hrs/week or whatever and rack up the hours, that does not mean as much as someone that has been involved with an EC for 2-4 years maybe 2-4 hours per week, it is about long term commitment and some schools will look at the amount of *years* spent doing something that you are passionate about and it may have nothing to do with medicine. Clinical experience/exposure is almost a must (yes, some people get in w/o this aspect but they are far and few...) so that you can actually talk/explain why you want to become a physician. The cliche I want to help people, I want to have a lifetime of learning is that just a cliche, they (adcoms) want real life examples of why medicine is what you chose and what will *you* bring to the table as a future physician. Of course that you like to learn, of course that you want to help people but medicine is not the only career that enables this, so that is why healthcare experience is really screened for. So, in a nutshell: do not wait until your senior year to get involved, start early in the process so by the time that you apply you will have a lot to talk about during interviews. Try to gain leadership experience why? because physicians will be leading in some form or fashion during their career. Get involved in something that has nothing to do with medicine, something that you really enjoy. Good lcuk.