Just an FYI for those who are interested, many of my students are reporting “extra hoops” to jump to get LORs from professors. And last week, a Prof I know very well from shadowing and getting the highest average in his course, denied my request on the grounds that we had not “worked together” on a daily, long term basis. So in my case, 4 months of class/shadowing and meeting ~ every 2 months since then, wasn’t long enough.
I don’t know if this is a Texas thing or what, but after hearing this from 3 different students in 3 different majors, pre-med, pre-nursing, and pre-nutrition, I thought I’d pass the warning along.
It’s good advice, Path. I believe it is probably regional as my MN professors have all said, “Do well on MCAT and let us know” … meaning don’t bug them if I get a 27. 
One I had in 2010 but kept in steady touch with, the other I last had in 2012 and he was my only “B” …
That all said, it’s really important to make sure your professors know you as a person, not just someone that rocked their classes with an “A” … mine all know my quirks. Good and bad because I spent a lot of time talking to them about their world, their PhDs, class, future bench work, guidance…
Oh and, yes, they all know me as the tall, blond, geriatric student who kicked the ass of the 19 - 23 year olds 
And not by a little … yeah, you, ya little SDN snobs… I kicked your ass too 