You must keep records of everything that affects your capital gains and capital losses. There are penalties if you do not keep the records for at least 5 years after the last relevant CGT event. If you make a net capital loss, you may need to keep your records for a longer period-for 5 years after any CGT event where you make a capital gain that you reduce by applying your net capital loss.
Keeping adequate records of all expenditure will help you correctly work out the amount of capital gain or capital loss you have made when a CGT event happens. It will also help make sure you do not pay more CGT than is necessary.
Keeping good records can help your beneficiaries reduce the impact of CGT after you die. If you leave an asset to another person, the asset may be subject to CGT when a CGT event happens to that asset in the future-for example, if your daughter (the beneficiary) sells the house (the asset) you have left her in your will.