It never fails. Every semester I train new students, and every semester, the same thing happens. I hand them a sheet of my guidelines for students. Listed in there is the following:
4. Write things down. You will be getting so much new information at first it will feel like drinking out of a fire hose. Here is a good rule of thumb: if I am explaining something, you should be writing it down. Also, if something is unclear to you, interrupt and ask for clarification.
Every semester I give out these sheets. They must go unread, because the first time that student learns anything from me...they don't write anything down. Usually the new, shiny lab notebook is closed. Often they don't even have a pen.
Look, kids. I do real good by you. I hold your hand through a protocol through at least two iterations (and let me tell you, watching someone sloooooowly pipette, or freak out trying to pick up a rodent by its tail for the 40th time, takes the patience of a saint). I not only write down protocols, I put them where you can find them. I hand them to you, printed out, physically, before each experiment. But even a printed out protocol a monkey could follow will not have things like "go to file: protocols: save as" written in it, it'll just say "save". That's why you need to WRITE IT DOWN. Even a written protocol will not have everything.
Write it down. Yeah, you say, no worries, I'll remember.
No you won't. NO YOU WON'T. Three days later? Sure. But three months later when you finally run the experiment again and need to remember whether it was red light or white light? You won't remember. Heck, most of you won't even have printed out the protocol again, because you won't have written down or read my careful instructions on how to keep a good lab notebook. And then you will come wailing to me about how you didn't KNOW where to save. How you didn't REMEMBER. And sometimes, when I tell you...you still don't write it down.
So don't look at me and get angry and defensive when I ask why you don't have a pen. Don't grump at me about how you won't need it. Shut up, swallow your pride. Write it down. Then when you forget something, and there it is in your lab notebook, all written down, and won't you feel clever? And won't I be relieved over not having to hold your hand? I beg you, students. Think of your postdocs. Write it down.