What is better for google: keep old not visited content deeply in the website, or to remove it?

[bele]

We have quite a lot of old content which is not visited anymore.

Should we remove it and have a lot of 410 errors which will be reported in GWT?

Or should we keep it and forget about it?

[irvingw]

Keep them. The more content the better plus the pages probably accrued PR as long as it's accurate info and not outdated. If these pages have PR you might want to consider streamlining the links on these pages to pass PR to the homepage or main landing pages.