Have been running an agency for the better part of a decade, we've grown from two to thirty-something people, and while we started with no insurance whatsoever, we now have policies coming out of the wazoo - and it's a double positive, as:
a) We no longer have to deal with "bullshit" situations. More often than not we notify the insurer and let them deal with it according to our wishes.
b) Because of (a), we can deflect most relationship damage that goes along with "bullshit", as it's not us being the aggressive assholes demanding payment, it's our insurers.
We spend maybe £10k a year all-in on insurance, but with several £M of turnover and several £Bn of client revenue (i.e. revenue they take through their sites) in the mix, it's an absolute bargain. We've only had to make two claims - most of the time, they make situations go away (negotiated settlement, etc.) before we have to make a claim, as it's in their interest (cheaper resolution) to do so.