This is how I feel, too. I'm leaving my posts and comments up; ironically, I used to habitually purge my profile every year or so because I was worried about IRL people finding me through my activity, but now, I'd prefer to just leave it. Even if I stop being active on Reddit, it's currently one of the best ways to find answers to niche problems; I'd like to keep my stuff accessible for anyone looking for extremely specific answers. I've been fairly private on Reddit, though, so it feels less sentimental and more practical. (Twitter, on the other hand... I never use it, but everything on it is way too sentimental to nuke.)