When it comes to running your own business, you need to ensure that you are keeping the correct documents and evidences and that it is being kept as securely as it is needed to be.
When it comes to accounting you should keep your documents for at least 5 years and be sure to keep comprehensive records that are easy to find should you need to. If HMRC ask you to show receipts for expenditures you have claimed for your business you need to be able to show them these quickly and if you cannot then you may find yourself having to pay money back and also having a fine.
Its not only for HMRC’s benefit that you should keep records. At times in your business you may need to refer to a similar case you had or to look up details for a previous client. It may be that you want to get in touch with clients that had made purchases off you before and so you need a place to store their details securely. Since GDPR came into force, you need to be able to prove that you have consent off everyone, that you can contact them in the future. If your database is quite old then you will need to update the information to ensure you are still ok to contact them in the future.