Loads of times, both personally and professionally.
Personally: 3 x burglaries and a mugging, when my car was stolen, when my ex assaulted me, when an officer came to my house to tell me my mother had died, to give a statement after witnessing a fatal accident, when a police officer involved in a chase crashed into my car and when me and my flatmates got done for growing cannabis (not a grow house - they weren't a thing in the mid-70s).
Professionally, I worked as a solicitor's clerk for a few years, and used to attend with clients at ID parades, police interviews and at crown court (with a barrister, of course). Met loads of coppers in that job.
A career change or two later, I worked for the clerk to the police authority where I live, was on first name terms with the chief constable and divisional commanders, and I set up all the consultative arrangements for the force area. Since then, with clients who've been DV victims or victims of serious anti-social behaviour.
I'd never considered myself to be someone who's had a lot of contact with the police, but now that I've thought about it, I have really.
Most of my contact was when I lived in London and I found the Met to be pretty shit. Since I became a country bumpkin, I've found the local force to be excellent.