I don't, never have, just write how much I take every week.
If I wrote a receipt for every customer, some weeks I would have 100 receipts.
You use a receipt book to keep them in and tear off the duplicate copy. You can get them in Rymans. If it is a cash in hand business then you need to make sure you have records for them to check if they decide to invesitgate your business. They will want to know every tiny detail if you get investigated and they will get you to prove you don't owe them more money.
This is an extract taken from the HM Revenue and Customs website:
HM Revenue & Customs: Self Assessment: Self Employed
What records should I keep?
Until recently there was no legal requirement to keep records for income tax, although Customs & Excise require registered traders to keep records for VAT. However, we have always advised businesses that it was in their own interests to keep all the records needed to help prepare accounts and tax returns. Rules introduced in the 1994 Finance Act mean that you now need to keep all appropriate records.
We will normally expect you to:
record all sales and other business receipts as they come in, and retain the record
keep back-up records, for example, invoices, bank statements and paying-in slips to show where the income came from
record all purchases and other expenses as they arise, and ensure - unless the amounts are very small - that you have, and retain, invoices for them
keep a record of all purchases and sales of assets used in your business
record all amounts taken out of the business bank account, or in cash, for you or your family's personal use
record all amounts paid into the business from personal funds, for example, the proceeds of a life assurance policy.
You will have to retain your records for five years from the latest date by which your tax return is to be filed.
