Why should I reach out to webmasters before disavowing links?

[RealSelf]

Almost all the blogs, and Google themselves, tell us to reach out to webmasters and request the offending links be removed before using Google's Disavow tool.  None of the blogs, nor Google, suggest why you "must" do this, it's time consuming and many webmasters don't care and don't act.  Why is this a "required" thing to do?

[Andy.Drinkwater]

It actually isn't required - Google have no way of telling if you have tried to contact webmasters and ask for a link to be removed. I have done many disavows without this (at the site owners requests) with fantastic results.

One of the Matt Cutts videos actually says that if you just notice a lot of links that are appearing and shouldn't be there, or you don't know where they came from, just go ahead and disavow them.

-Andy

[seovp]

If it is unlikely that a webmaster will reply or looks as though the site is trying to hide contact details then you may not need to contact webmasters before disavowing as it is a waste of time. But in a lot of cases it is more beneficial to you to have a bad link removed than to just disavow it, so it can be worth contacting a webmaster to remove a link.

If you are under a penalty though, Google will want to see you are doing everything you can to remove unnatural links and may want to see evidence that you are trying to contact webmasters to remove links rather than just putting everything into a disavow file, because links that are disavowed can just be taken out of the disavow file and be 're-avowed'.

Kind Regards