What insurance must tradespeople have?

Hi everyone,

I am asking about the precautions people should take before allowing
any tradesman onto your property, particularly checking that they
are properly insured. In order to do this, it seems that it
can be quite a lot of work?

I am mainly going by pages such as these:
- http://www.fairtrading.nsw.gov.au/Tenants_and_home_owners/Home_building_and_renovating.html
- http://www.fairtrading.nsw.gov.au/Tenants_and_home_owners/Home_building_and_renovating/Selecting_a_tradesperson_or_builder.html

The first thing to do is to get their licence number and verify
that they have a current suitable licence:

That's fairly easily, but what about checking that they have
all the proper insurance?

5. Do you have proper insurance?
It is important to check the contractor has all the necessary insurance
cover to protect you and your home if something goes wrong.
Go to the Insurance page for an explanation of the different issues and types of insurance:
Home Warranty Insurance
Builders All-Risk Insurance
Public Liability Insurance
Workers Compensation or WorkCover Insurance
Kit homes and Insurance
Contracts Insurance

There is quite a lot of detail available on "Home Warranty Insurance",
which by law they must give you if the contract is worth more than $12000:
- http://www.fairtrading.nsw.gov.au/Tenants_and_home_owners/Home_building_and_renovating/Home_warranty_insurance.html
- http://www.fairtrading.nsw.gov.au/Tradespeople/Home_warranty_insurance.html

That's good, but what about the other types of insurance listed above and at:

Can anyone tell me their experiences in finding out whether their
tradespeople were properly insured? E.g.
- What type of insurance "must" a tradesman have by law, if any?
E.g. if it's a company, I think they must have Workers Compensation insurance?
- There are quite a few insurance categories above, and it can be hard
to know which one a particular class of tradesman "should" have
(whether or not by law), in order for you to be protected.
E.g. "Should" all tradesmen have public liability insurance
at the very least?
- I guess you should ask to see their certificates of insurance, so that
you can then contact the relevant insurance company to verify that
they are currently insured?
- When should you ask for this? Before you even let someone visit your home
to even give a quote? Or before agreeing to any paid work?

E.g. what happens if someone injures themselves just from
visiting your home to give a free quote?

I know that tradesmen are sometimes extremely busy and can be hard to
get a hold of, even to just get them to visit you for a quote.
Will they try to fob you off if you start asking them for insurance details
before they've even visited you for the first time?
- What about during emergencies, e.g. when a water pipe has burst.
Can you only verify insurance details with an insurance company
by calling them? I'm assuming you can't do it on the internet?

- What about when you are dealing with a company, which will supply you
with contractors, subcontractors, etc.
Do you need to do a licence check and/or insurance check
against every single person who will visit your home? Or are you
covered if you do these checks against just the company?
Hopefully we will get some comments on this, as I waiting for some on my post on Tradies Compensation, where the LL may be liable.