Good grief! Never thought I'd see this as a topic in the Manband Forum! I work as a commercial insurance broker, having sort of drifted into an insurance company job back in 1976. Whether it's personal or business insurance, my advice first and foremost is to talk to an insurance broker. You won't necessarily get the rock-bottom cheapest deal every time, but you will get correct advice based on your needs. I arrange all my own covers via an insurance broker (no, not me, someone I trust) and I'm happy the price is as sharp as it can be and the cover matches my needs. Now, the renewal vs. new quote conundrum. Yes, there are two pricing models out there, new business is heavily discounted to draw you in and then load the price at first renewal. Therefore my second piece of advice is to get quotes from other markets whenever you are presented with a renewal bill, and use them to negotiate something acceptable. A good broker will have already done this work for you, but if you've time to kill, it's worth doing anyway. Just make sure the details you enter are exactly the same each time. My third piece of advice - this applies if you are buying cover online or direct - is caveat emptor. You really need to be an expert to understand the fine detail of the contract you are entering into. Beware conditions, warranties and hidden excesses. Cheapest is often just that, whereas what you probably need is something which actually works in the way you expect it to.
(just read what I have typed - what a tedious load of drivel. I'll post it anyway.)