If it's not important enough to message me twice, it doesn't need a sub-week-later reply. (Obviously, some caveats about important people, routine work messages, etc.)
I generally get back to people or read messages, but only when I spend an hour going through things when I have free time. I don't feel obligated to respond to random messages on their timeline.
Totally this. I also apply a similar rule to phone calls - barring few exceptions (family, expected important communication), I pick up only when I feel like it (and most of the time, I don't). If something is important, one can text me instead (thus letting me decide whether or not I consider it important too).
