Indemnity insurance for a sole trader is the same cover a company buys with one difference that changes the stakes: there is no company between the business and the person. A claim above the limit is the sole trader's personally, which makes the limit a decision about personal assets rather than about a balance sheet.
No corporate veil
A limited company's liability stops at the company. A sole trader's does not. That is the single most important consequence of the trading structure for insurance purposes, and it argues for buying a higher limit than a company of the same size would, not a lower one.
The policy follows the person
The insured is the individual, trading as whatever name is used. Changing trading names does not need a new policy, but incorporating does: once a limited company contracts with clients, the company should be the insured and the old personal policy needs run off cover for the work done before.
What a sole trader typically needs
Professional indemnity where the work is advisory or produces something a client relies on. Public liability where clients or the public are ever physically present. Employers liability if anybody works for you, which is compulsory. Plus tools, equipment or stock cover depending on the trade.
Questions people ask about indemnity insurance for sole trader
Does a sole trader need different cover from a company?
The same covers, with more reason to buy a higher limit: there is no company between the claim and the individual's personal assets.
What happens if I incorporate?
The company should become the insured going forward, and the personal policy needs run off cover for the work done before incorporation.
Is employers liability needed for one helper?
If they work for you rather than for themselves, yes, and it is compulsory with a penalty for each day without it.