[Q] When to disavow backlinks

Hello guys, i have a new MNS and started building links.However in WMT it found 193 backlinks.There are still no web 2.0s i've made, i'm waiting for them to get indexed, but 5 days ago i've found 73 backlinks from scoop.it don't know how, my rankings moved to 26 spot, and now 2 days in a row they drop +5, it's on 35.It also found in the beginning 10 backlinks from a website babyatthecity.com which i've left only because it has some PA and DA.Should i disavow some backlinks or this can't negatively impact my MNS?

Or i shouldn't disavow anything 'till i get hit? lol

Open up those links, see what linsk to you. If it looks like something that can hurt you then you should disavow - auto generated content or something like that. You bought a fresh domain for this project? If yes, then it's really weird you have links, might be someone ripping off your content.

I bought this domain 2 yrs ago but i gave up on that project, and when it expired i bought it again.So never mind if it doesn't have high spam score on Moz for example and has some DA and PA i should disavow it if it looks spammy because of manual actions?