but interesting someone says, no insurance for Twenty years ?
I wouldn't recommend no insurance in general, but the risks in my case have always been minimal.
The vast majority of my customers are business customers who I've had (and personally known the owners of) for 10 years or more. They're all very loyal customers and, the relationship is such, that I'm very open and frank about all the pros and cons of any work I do for them, including any risks (like backup limitations), which they agree to take responsibility for.
I've never lost a customer and I rarely take on new customers anymore because I already have more work than I need. I've never advertised (all new customers in the past have come through recommendation), so I don't do work for 'strangers' or the public in general. I do have a handful of residential customers, but they're generally either people that I know well or people who have come through other people or businesses that I already do work for.
And, though there's always a first time, in 20 years I've never made a mistake that cost a customer, nor have I ever accidently broken a customer's property.
I do accept the need for insurance though -- it's one of life's necessary scams unfortunately -- and I have considered it on occasion. If it's cheap enough, I may take the plunge but, to be honest, I'd rather self-insure by putting some money aside to allow for breakages, etc.