Hey! I'll just let you know how I did it at my school and my own LORs I collected.
BTW: Does your school have a pre-health advisory committee? in which case, it would be best to go through the committee and send a Committee Letter to AADSAS to be then sent out to all your schools. All the schools I applied to accepted a committee letter. If you do have an pre-health advisory committee, DEFINITELY have them submit a committee letter on your behalf. It shows that you have the support of your school. Plus, it's just a lot less hassle in making sure 1 letter was received by AADSAS than 3 or 4. And the people on the committee are pretty knowledgeable about the entire process 😉
I'm not sure if this is the same at all colleges, but at my school, all my LORs were sent directly to the head of the committee. I was recommended to submit 1 bio and 1 chem (the 2 sciences; make sure you got GOOD grades in these classes), 1 from each major/minor (if you double majored/minored), 1 research (if you had any), 1 from a dentist you shadowed (better if it's a pretty extensive shadowing period rather than just a couple hours), and any other from internships/experiences you felt were significant (make sure it's a strong LOR).
For some people, it was pretty straight forward because they were bio majors and had researched under one of their bio professors, whose course they also did well in. So that was like knocking 3 down with 1 stone. (I actually might have gotten a separate LOR from a different bio prof, so I would have 1 research LOR and 1 bio LOR). Then they might have minored in chem. And they were done.
For others like me, it was a bit more work. I had a non-science major, so I got one from my major advisor. I minored in chem, but I never took a course with my research advisor (who was also a chem prof), so I had to get separate recommendations for both. But because research does not technically count as your 2nd science (especially since mine was not based in bio), I got another one from a bio prof. Then my dentist LOR. So, in total, I collected 5 LORs. Which is actually a lot in comparison to others... but that was just my own case based on my own personal situation. And just a reminder, we were all warned prior to submitting LORs not to submit them for the sake of having a lot of LORs. Sometimes too many can do the opposite effect of a few really great ones, which would have been a lot stronger if they had stood alone.
If I had sent in the letters individually, it would have been impossible to have AADSAS accept them all. But because they were sent to the committee, which then worked to compile them to write a committee LOR, it was doable.
ALSO, I know people who wanted to take a year off before graduating and thus had started the application process in their senior year. They had collected and submitted all their LORs etc., but things changed, and some decided to postpone applying until the following round. After notifying their advisors of their situation, they were able to apply using the same LORs previously collected because the committee held onto their files from the previous year. They also added/updated their LORs with whatever they had been involved with during their time off (i.e. work supervisor, etc.) I'm not sure if the OP is referring to a situation like this when asking about keeping a LOR on hold, but if your school has a committee and a similar situation arises, it really should be no problem.
If you're still in undergrad as a freshman (let's just say) and wanted to get a LOR from your Fall Intro Bio prof and then keep THAT LOR on hold until you apply, I would refrain. Personally, I think schools would want to see recommendations from more recent courses (hopefully you're getting even better grades or still doing as great! 😀 haha) because the prof should have a better notion of you as a student later on in your college education. And you never know if you'll develop a great relationship with another prof later on, with whom you have 2 or 3 courses/labs with. You might not only do well, but also go regularly into their office hours to ask questions. That prof (while s/he might be the same prof from that Fall Intro Bio course) would definitely have a better idea of you as a student, how you've grown, your character, integrity, work ethic, etc. after having you as a student a couple semesters down the line vs. right after just one semester. And you would consequently have that much more of a kick ass LOR.
I wouldn't downplay the significance of the LORs. While gpa and DAT scores are definitely important, schools consider applicants comprehensively, especially when so many applicants have similar numbers and stats. The personal and LORs show a different side of the applicant (prior to inverviews). I always considered the latter 2 portions important in creating a sense of voice and image of the applicant that goes beyond hard numbers. I know people who were told at an interview that they had received AMAZING LORs. A GREAT LOR says a lot (I think) because it's not YOU selling YOU, it's someone else (who is in a respectable position) RECOMMENDING YOU on your behalf. So be selective in who you ask and make sure when you as a person for a LOR that they can definitely write you a good one. Don't be afraid to ask straight out if they would be able to write a good LOR, because if s/he can't give you a straight answer, maybe s/he may not be the best person to write you a recommendation. It might be a little awkward, but it's better to know and get a strong LOR than a half-assed one. But be polite and respectful about it. In some cases, you have very little choice. But if you do have a choice, BE SELECTIVE.
AND START EARLY!! I can't remember the exact month, but in my experience, earlier is always better. It's just considerate of their own busy lives. After all, each LOR is a FAVOR they are doing FOR YOU. And think about how many students they may have, and how many other recommendations they may have to write. You want them to take as much time and consideration possible for YOUR letter. So ask early (especially if s/he may seem like a popular prof for LORs), and remember to politely check in and remind them to submit the LOR throughout the process. It's ultimately YOUR responsibility to check to see if they remembered to submit the LOR to the correct address on time, so be diligent if you have several LORs to take care of. AND always remember to send a Thank You card after.
I know my committee had their own deadline which was around the end of fall/spring semester. If you're submitting directly to AADSAS, let them know to submit the LOR on or soon after the first day AADSAS releases the application. (In this case, you should have already began looking for LORs at the beginning of prior Spring semester latest, just to be safe. But that's just my opinion). You definitely don't want to be scrambling for LORs during the summer. And this way, you'll find out if anything goes wrong with processing your LORs sooner than later.
I'm not personally familiar with Interfolio...but if you have a committee to go through, it shouldn't be a problem. If you don't, then maybe you can let your profs know when you plan to apply and see if you can work something out with them (ie. Communicate and keep in touch. Don't drop off the face of the earth and pop up out of nowhere demanding a LOR). Or a third party service like Interfolio could work too I guess.
I realized that this post is really long... and it's one of my first posts. haha. I don't usually spend too much time here in the forums, but I remember I was confused and worried over getting my own LORs when starting the app process (mainly cuz I felt like I had to seek out so many and the sometimes awkwardness of asking). But your profs that you ask for LORs usually are the ones you like/know well/got good grades from, and for the most part, 😛 they want to see you succeed as well. So, it's no big in the end. And thankfully, mine were very on top of things, so I didn't have to chase any down to submit them by the deadline.
I hope this is of some help? (Probably not so much if you're not submitting a committee letter ^^;😉. Again, sorry for the loooong post.
