A will is a document most people buy once, reluctantly, in a market that sells the same product at three very different prices. There is the kit from the shop or the template online. There is the will-writing company that comes to your kitchen table. There is the solicitor's office. From the outside the finished documents can look nearly identical, which is exactly why the market is confusing.
Rarely the wording. It is the formalities. A will must be signed in the presence of two witnesses who are both there at the same time, and a gift to a witness, or to a witness's husband or wife, fails. People sign in the wrong order, use a beneficiary as a witness, or staple in a later change that unpicks the whole thing. The cruelty of these errors is their timing: they surface after death, when nothing can be corrected and the family bears the cost. If your estate is simple, your family situation is simple and you follow the signing rules to the letter, a do-it-yourself will can be perfectly sound. The risk is not that it probably fails. The risk is who pays if it does.
Here is the fact that surprises people: writing wills is not a reserved legal activity in England and Wales, so anyone can sell them without being regulated to do so. Reputable will-writing firms exist, and some belong to voluntary trade bodies with codes of conduct and insurance requirements. Voluntary is the operative word. If the company folds, the question of where your will is stored becomes yours to solve, and if the work was poor there is no automatic ombudsman route behind it. When a will-writing firm quotes you, ask what insurance it carries, which body it belongs to, and where the document will live for the next thirty years.
Regulation, first: a solicitor's firm answers to the Solicitors Regulation Authority, carries compulsory insurance, and sits behind a complaints route that runs to the firm first and then the Legal Ombudsman. But the larger part of the fee buys advice rather than typing. A solicitor will ask who might feel entitled to claim against your estate, what happens if a beneficiary dies before you, how a second marriage or stepchildren change the picture, and what to do about a business or a property abroad. They will also give you a straight answer on the things a will cannot do, which is its own kind of value. Fixed fees for wills are common, so the price conversation is usually short.
Single, one property, everything to a spouse or children equally: the cheap routes can serve you if you respect the formalities. Second families, farms, businesses, foreign assets, or anyone you intend to leave out: pay for the regulated advice. This site lists 2,926 solicitors' firms and shows which offer will drafting near you. Start at firms in your area, or describe what you own and who it is for, and let firms quote. Before any appointment, write down your assets and your intended gifts on one sheet. Every good will starts as that list.