I resolve to not erase any memories. I want to never have to face the dilemma of wondering if something happened in my past that I had redacted. The only way to protect myself from this possible stressful situation is to believe I am not the kind of person who would ever tamper with my memories. (The "Golden Age" novels have a good depiction of the possible problems associated with discovering that you are the kind of person who has his/her memories redacted.)
Maybe I'm reaching here, but there also seems to be a parallel between the process of resolving to one-box in Newcomb's problem and that of resolving to not redact in an Eternal Sunshine scenario. It is the act of resolving, of making oneself the kind of person who one-boxes, or non-redacts, that generates the benefits, not taking the one box or actually refusing to redact memories.
I wouldn't know. In a world with this technology no one can ever know that they don't have some or maybe a great many erased memories. The only defense against this uncertainty is a self-binding constraint placed voluntarily on myself.
Of course this is a limited defense, but short of a binding legal contract, its the best I can do.
So you're saying that you cannot imagine having memories so traumatic that you would prefer to erase them from your head (and, say, give yourself a written record so that you aren't tormented by the missing information). I'm not talking about a painful breakup here -- consider the most inconvenient possible world, e.g., one in which you have memories of being tortured for months or years on end.
Even with memories that cause PTSD, it's not so much the forgetting that helps as the being able to reconsolidate the memories without them being hooked into trauma.
What if you could choose which memories and associations to retain and which to discard? Using that capability rationally (whatever that word means to you) would be a significant challenge -- and that challenge has just come one step closer to being a reality.