I might, or might not, need letters of recommendation for a PhD application in the future. My plans are vague, I am just finishing my master's and planning to work for a while before deciding.
There are just a few people who could write a letter about me that doesn't just say "they did well in class". I would like to keep the option of asking them for one, even after being out of academia for a year or two (still doing research as part of my job).
I would also like to know how strongly they would be willing to recommend me. I worked with them on only one project. Even though they gave me very good feedback, I imagine they might not remember me well enough to write a good letter if I ask them after a long time. We work in somewhat related, but very different, sub-fields of computer science.
Should I contact them now, without having a clear plan in mind, and ask if they would be willing to recommend me in the future? Is it just a waste of their time if I don't yet have anything concrete to ask for, or any precise plans or institutions to mention?